Mmm-hmmm. And even if they didn't eat the anemone, they might gig it into going walkabout, which might be disaster if it puts a tentacle into a powerhead.
My recommendation would be green star polyp, which will coat your rocks in 'green lawn', and purple and greenstripe mushrooms, which are discosoma species --- discosoma neglecta is also a pretty one with some bluish overtones, but not common in the hobby. These reproduce when cut, are nearly impossible to destroy and are probably as prolific as aiptasia. They'll coat everything in frilly color and whether or not your angels will nip them, I don't know. I'd at least either buy a large rock covered with them or use an eggcrate shield to protect your mushrooms while they grow abundant enough to withstand predation.
You MIGHT consider starting your tank without the angels, and get a good mushroom population before they go in. Fancy mushrooms might not survive the predation, but discosomas may well.