Maybe when she comes round to show you the materials she got, they won't be too different to what you had in mind yourself anyway. Or ask her to incorporate your pieces into it to. I know it's lovely of her to make it for you, but you still want to ensure it's what you want.
Good idea. If you partner's chain is maybe more sentimental, being from her aunt, then it's important she's happy with that. Getting your aunt to do yours and BMs is plenty for her to be doing (as well as a lovely gesture)
I would wait and see what she has first if she already has them ordered, you might find that you really like them and are happy enough to go with them.
If you don't like them then just say they are lovely but you would really appreciate if she could use the ones you have instead or if possible maybe try and incorporate what she has and what you have into one, that way everyone is happy.....
Maybe you could do like a double layer of pearls for the bun style??
I would invite her round, make a bit of an evening of it, have your stuff there, with pics of what you want/ would like and arrange some back up! ie: Have a friend or two/your bridesmaids there too, briefed before hand to ooh and aah and interject at all the right moments with such lines as "oooh I really like that idea about the bun, with the pearls, so simple, so classy, so elegant,... dont you think aunty"? etc etc. subtle, but she'll cave to your wishes if faced with several agreeing opinons... sly-ish I know, but im learning that this weddingplanning stuff requires a little sly manipulating now and again to try and keep all the waters smooth! stress!