Who gets corsages/boutonnieres?

Corsages:

MOB

MOG

Grandmothers (occasionally, not mandatory)

Boutonniers:

Groom

Groomsmen

Ushers (optional)

FOB

FOG

Grandfathers (also optional)

Everyone else I would say no.

It's kind of situation dependent, I think, and up to you.

for us it'll be parents and grandparents.

Unless you're particularly close to an extended relative like an aunt or uncle, I wouldn't spend the money.

None for the officiants.

Like I said, you'll have to decide for yourself.

Pianist?

Parents, Grandparents, Groom, Groomsmen, Ushers, and Ring Bearer are the definates I would say. Then something smaller and more simple for Host/Hostess(s), Guestbook Attendants (if having one), Readers (if family or friends), Muscians (if family or friends), Punch Pourers and Cake Cutters (if family or friends).

I agreewith bride to be,maybe just add the ring bearer.

Since I'm making my own, I'm leaning towards parents, grandparents, and wedding party obviously. If I have any flowers left over, then I might get fancy and give some to aunts, uncles etc.

Same line... Would adult sons and their wives receive?

At least offer!! Though your wedding officiant is (or at least should be) compensated for his or her services, the wedding officiant is a vital member of your wedding party with the most important and significant role in the wedding ceremony. He or she should be invited to be in your wedding photos and should be appropriately dressed to match the wedding party (including a boutineer).

What about brothers and sisters?

My only sister is in the bridal party, as is the groom's older brother. But his older sisters (much older) are not in the bridal party.