hosting your own bridal luncheon?

No it is not acceptable.

Go to the tea parlor with some girlfriends as a fun Saturday afternoon thing together not wedding related.

I would let your MOH know what you are thinking and help her plan it so you get what you are looking for. I know that might out of the ordinary but you like what you like and there is nothing wrong with that, plus your MOH might be relieved she does not have to plan this.

It's frowned upon.

If someone offers you a shower, then just let them throw it any way they want. Showers are nice ,but not 100% necessary.

This isn't something you have to worry about - focus on the wedding

Agree with PP.

A bridal luncheon is actually traditionally hosted by the bride to honor her bridesmaids. If that's what you're doing, go for it. If this is a shower disguised as a lunch then don't host your own.

Is this what you're talking about??

A bridal luncheon is hosted by the bride to thank her bridesmaids for being part of her wedding. So yes you absolutely should host your own bridal luncheon!

It's also a good time to give them their gifts!

I had a bridal luncheon that my mom and I hosted. Technically it was a brunch but basically everything Jeanne said.

It was the morning of the rehearsal dinner, we rented a room at a restaurant and had a fixed menu and I gave the bridesmaids their presents (robes, champagne flutes etc)

This is not the same as a bridal shower.

It's definitely not a shower disguised as a luncheon. I just want to get all the important ladies together the day before the wedding for some fun and food.

if it's a "bridesmaid luncheon," is it acceptable to invite moms, grandmas, etc, or just bridesmaids?

I'm hosting a bridal tea for my ladies as well. I'm calling it a "thank you tea" so they know I don't want gifts. No formal invites for the same reason...they just seem more pressure-filled to me.

Ok OP I take back my initial comments then.

Then yes you can host this, I think you can invite whomever you want since you're footing the bill. And as far as invites go you can make them say whatever you'd like, lots of cute custom invites on Etsy where the seller will make the wording however you want.

I did. I invited my grandmother, aunt, my MIL and my mom

I would say yes. It sounds lovely.