I am a one-dwarf band. That is, I have one VIP account for Thea. All of the other players in my band are on free-to-play (F2P) accounts. Currently I have eight band members, Thea plus seven add'l musicians. Since every account requires a unique email address, and I have a few different web domains, I generate an email address there. You can also create multiple Gmail accounts, or whatever. Since Standing Stone Games doesn't send you a 'confirm this email' email when you create the account, there's actually no requirement that the address is valid!
I run on both Mac and PC equipment. When I'm running my full band, I'm running on a three-year old Asus gaming laptop with 32 gig of memory. I'm running at the lowest graphics setting, which greatly reduces CPU load. It has no problems loading all eight LOTRO instances. I'm planning on taking the number of band members up to 10 or 11. On occasion I borrow one of my wife's F2P characters when I need a 9th for some songs.
I currently use three LOTRO plugins: Poetical when I do lyrics, SongbookBB sometimes for song management, and Bandaide. Bandaide is interesting: as I load up my alt musicians with their parts, it shows me who has what instrument and song loaded, so it shows me if I screwed up and someone has the wrong song loaded! Saves some embarrassment.
There's two versions of Songbook: Songbook and SongbookBB. BB is slightly newer. Functionally, they seem identical. One thing that you have to be careful of is that they both require a catalog of your songs to be generated before you open the plugin within LOTRO. So whenever you create new songs, or before you're going to do a major show, you need to run the generator for every character in your band! If you have a lot of characters in your band, this can take a lot of time, so be sure to have that time budgeted before the show!
Also, be sure to practice with Songbook (or BB) before you're going to use it in a show so you're very smooth with it. It's easy to get flustered, and that's not good before a big event!
I'll be talking more about my band as time goes by.