Does my sister in law have to be a bridesmaid?

No you don't at all, have the people you want as BMs with 8 already sure they will understand. You could always ask them to do something else - reading or the like

My FSIL is my MOH but not because she will be my SIL she was my Brest friend for years before me and FH got together

No I don't think you have to. Especially with 8 already...10 would be really hard to manage! I think if they're excited to help maybe they can greet people and hand programs to them at the beginning, do a reading, and be points of contact for your other vendors.

Neither of my sisters in law will be bridesmaids but they each have a daughter who will be a flower girl so they'll be walking the little ones down the aisle. :-)

No you don't. You could ask them to do readings or something like that if you want to have them feel included.

I have a smaller attendant party but invited a few other people to get ready with us (very low-key day) to join in the fun.

No. 8 is plenty.

Nope. Mine wasn't. Let them throw you the shower, though, since they want to do something!

Nope, my FSIL doesn't really speak to me, No way in hell I want her as a BM.

Mine aren't. I have asked the both to do readings. I'm close with one and not to the other so to avoids drama I decided abainst

Simple answer. NOPE. My own children were not in my wedding. I have 3 children. I would have liked my daughter to be a bridesmaid, she is 17 and my one son to be ringbearer he would have been 5 at the time. But my other son is 22 and he simply is not my husbands friend. He chose his friends to be in the wedding. We only had 4 on each side.

You dont have to! Pick whomever you want up there! I have my BFF who is my moh, a good friend and my sis as bms and also my fsil but we wanted family up there so for me it worked out!

Nope, pick who you want! Back in the day, my mom was told she had to have her sister-in-law and cousin on husband's side (that she had never met at the time) in her bridal party. While it was decades ago and she loved her wedding day (and her sister-in-law!), when I asked her about is she still says she wishes she hadn't been "told" who would be in her party. My mama had no bridal balls. So invite who you want!

I included for the sake of being polite.... It has not gone well to say the least. So follow your gut with this one and if you don't want to include SIL don't include her.

I'm asking my sister/sister-in-law to do my bridal shower because I didn't ask them to be in the wedding party.

No. Put who you want in

Not if you are not close. I didn't ask mine, although she is nice enough-- we're just not close.

I'm not super close with mine, but we're getting closer. She's one of my bridemaids, she wanted to be one and I was more than happy to have her

FH has 7 sisters and only one of them is in the bridal party. She is the only one I am close to. You can do what you want. FH also only has 1 of his 4 brothers.

Nope! Mine sure as heck isn't

Don't do it because you feel obligated. I did when I married my ex and his sister was a fucking nightmare, especially after her engagement was called off half way through mine. She tried making everything about her and if she didn't get her way, she would refuse to help with anything. She even bitched because I didn't have her cousins in the wedding. It was a horrible experience to say the least.