Really anybody ''can'' wear a bout. To be safe I would suggest
- the groom
- the groomsmen
- the dads on both sides
It''s also a nice idea to include the grandparents in regards to corsages and bouts just as a way to make them feel special (I work in a flower shop and we often suggest that) The above list outilines the ppl who generally recieve bouts but you can include anybody that you want. If you decide to include brothers who are not in the wedding party just remember that you should also include sisters who are not in the wedding party. Really bouts/ corsages are just a nice way to recognize people and include them if they are outside of the wedding party.
I would personally not include one for the officiant but once again personal. If you are trying to cut costs you can limit it to just the wedding party (but I still think that grandparents are nice to include if there are any)
The officiant usually doesn''t wear a bout unless he wears a suit rather than a robe.
I think that beyond the members of the wedding party, it''s your option. If you would like to honor your brothers (and other family members) in that way, there''s no rule that says you can''t. There''s no rule that says you have to, either.