I think whether it would be "normal" for Dad to go to BM's house is dependent on their relationship.  The SDs here are years away from prom, but if the relationship between SO and BM remains as is, it would be perfectly normal for SO to go to BM's house.  Unless BM is high conflict, I don't see any issue with dad going to the place where they're taking pre-prom photos.  I'd play that one by ear, including asking the SD what she wants.  I think whether Dad should be paying for part of prom depends on his financial situation, BM's financial situation and his relationship with SD.

As for the prom extravaganza, what you're describing was the norm for proms at my high school.  I grew up in an affluent area, and most girls had dresses that cost upwards of $300 and some had dresses that cost MUCH more than that.  Many girls got their hair and makeup done, often at very pricy salons. Prom was held at a downtown hotel ballroom and we went on hired buses (nice buses, not school buses).  Tickets to the prom alone were nearly $100 a person.  Prom included dinner, so we didn't go out to eat, nor did we need limos since we were going on buses (that was a control thing on the part of the school - they also had security at the hotel so no one could sneak out and they deliberately held the prom 30+ miles away from the school to reduce the chances that non-students would be sneaking alcohol in to us at a closer venue).  I don't think it's reasonable, but I would say that most girls at my HS spent upwards of $500 on prom, and this was several years ago.

Almost every divorced parent I know goes somewhere (often to BMs) for pics. It isn't a day to say "my day or your day", it is a special event they both can be a part of.

My friends two girls did prom recently. Mom and dad each agreed to pay for certan things. I think mom dress, since she went shopping with the girls and dad did hair and nails. His kids are angels so decided the limo was too expensive. I think how much they want done is dependent. I had my hair done because my hair is sooo frustrating. The one year I didn't I cried getting ready because I made myself look like Shirley Temple. I did my own makeup for the next but had my hair done.

Yes, I think it's normal for a dad to get a gander at his kid on her way to the prom -- either at your place, BM's place, or somewhere else.

If you aren't comfortable with him going to BM's house, maybe suggest a little get together for the group at your place or some reasonable alternative. There's no reason they can't pop by your place for photos, unless it's really out of the way.

As for chipping in...weddings, proms, graduation gifts, etc., have all gotten ridiculously extravagant. I believe if you give the kid something extravagant for junior prom, the next one will be more extravagant, and then the wedding....whew! Forget about it! Parents set themselves up for these expensive things by going too big for the first event.

Forget about what everyone else is doing for their kid -- you have personal finances, personal circumstances that mean maybe you can't or shouldn't do what everyone else does. He should offer what he thinks is REASONABLE -- half for the dress up to $100, for example. She can't go without a dress, but she can go without a limo, pedi and manicure, etc. If you show the kid now that there are parameters, financial boundaries, you'll be glad later.

A better option might be to tell SD/BM you'll chip in up to $150 (or whatever) and SD can spend it as she likes -- on her dress, her hair, whatever. That way you aren't concerned with paying half of what could become a big bill, but you're still giving her choices and contributing.

It isn't healthy for parents to treat kids to proms that are like red carpet events. You setup your kid for expectations you might not be able to meet. And they simply don't need to spend so much to have fun! Think back to the proms of the '70s, when no one had their hair done, dresses were simple, etc. Those people still had fun. It would be nice for new generations to get back to something more simple so even the poor kids can feel part of it.

I think it's normal for dad to go to BM moms house or wherever the meeting place is for pictures. It won't happen in my or my DH's case...cause we have too much conflict. But I do think normal people should do it.

As far as dad contributing....it depends on alot of things. Does he pay a high CS? My DH pays alot....so I think he would maybe pay for one thing or hand her $100 to spend on whatever? I receive alot in CS and wouldn't ask Ex H for a thing.

I guess the amount of money contributed would also have to factor on...does she get good grades? Behave? Clean up after herself? If the answers are yes, I'd be inclined to give more.

I did the limo, dress, hair make-up, nails, fancy dinner out, etc. 20 years ago....so that was a HUGE thing where I lived even way back when. Do I think it's just automatic that every kid gets hundreds of dollars to spend on prom? No.

1. SD’s prom is on a non-parenting weekend. A group of kids/parents are meeting to take photos of the make up couples. Is it normal for Bio dad to go over to BM’s house or meet where they are taking the pre-prom photos to see SD? 

Yes.  His daughter and since the event is occuring on time that is not his it is not abnormal for him to go take pics.

2. Should bio dad offer to pay for half of the Expenses(dress/makeup/hair). If not what should he pay?

This is a joint call between you and your DH.  I tend to land on the side of CS is what the NCP provides to the CP for all kid related costs.  If he, and you, want to do something special... I would suggest that you do it directly with the Skid Vs participating in BM's related efforts.

3. Typically what is reasonable for a junior prom to cost(dress/hair/makeup etc)?

I have no idea but... it depends on many things.  Income of parents, demographics of the school, etc, etc, etc....

I think there are a few answers here but a lot depends on the relationship and how everyone gets a long 

First Proms have gotten way out of hand and have become the cost of a little mini wedding.   

My thought regarding the costs, I think it depends on each family's budget.  With that said I think it would be nice to split the costs HOWEVER, reasonable costs not 300 dollar dresses and limo's and hairstylists.  If the BM wants all of those things then I would say offer an amount you and your husband feel is reasonable and if BM wants to have a lavish evening for her daughter past that let her foot the rest of the  bill herself.  

As far as dad going to BM's house for pictures I think that depends on the relationship and how you all get along.  If everyone gets a long I would say go but my question first  would be do you all get along and if so why wouldn't you be going also? If you aren't invited too I would say your husband shouldn't need to be going either.  If that is the case or if BM is high conflict then I would say have SD stop by your house or in my town the parents all stop by the prom at the begining of the night if your town is like that too you could do that.  

I also agree that you and your husband wouldn't need to be there for the getting ready pictures.  No man really wants to do that LOL ..  I say he only needs to see the finished product when she is all ready and with her date.  He and you and most of the parents really don't even need to be inside in fact most pictures weather permiting are outside in the yard and most parents never go inside the house at all.

In our town we have a Park at the lake where everyone goes to take pictures for Proms and weddings.  This clears up a lot of those types of situations because it is a public place that everyone can go to see the Prom couples and get pictures and no one feels uncomfortable.  Maybe there is a public park you could suggest also.