I was questioning the sweepers on mushrooms too but a quick googling brought up one r2r thread of someone whos mushroom actually spilled its guts out to attack another coral, nota sweeper but it was really really long so I classified it as having something akin to a sweeper.I've never heard of ricordeas having sweepers. They'll sting something if it directly touches them, but that's it, and they may not even do that. Ricordea florida are well-behaved and very colorful, I highly recommend them in your sandbed. Maybe not on your rockwork in case they multiply fast for you. Just give them some rubble to grab.
GSP will absolutely stick to your back glass, and your front glass, and your everywhere glass. I've read it's easy enough to remove from glass, so if you don't let it touch and get onto your rockwork, it should be fine to have. It can sure look nice.
Blue sympodium would only take over your tank if you gave it a very long time and no competition, and maybe not even then. Blue clove polyps are the super invasive ones.
Lordhowensis is the full species name of acan lords, AKA micro lords. Those are micromussas.
I'm hoping GSP is easy to peel off glass, that's what I was informed of earlier in this thread so hopefully I can keep it off the sides and front, only concern is I do have some of my rockwork kind of close to the glass to I might scrap the idea all together.
Noted on the blue clove polyps vs sympodium.
I just included the "lordhowensis" note to remind myself what the full name was lol, not the most consistent sheet innit.