To answer your first question, if you are REQUIRING bridesmaids to have their hair and make up done, you pay. If they are given the option they pay.

I don't know about flower girls because I didn't have one.

Anything that actually has to do with the wedding...apparel (such as te shirts you bought) or anything used specifically for pictures does not count as a bridesmaid gift. You can find them each something personal for them.

I would do groomsman attire a few months before te wedding.

I grew my flowers myself, I practiced a lot on what I wanted for a centerpiece look. I ordered some roses wholesale from sams Club. They looked great. It took an entire day to do flowers though.