I agree with fishfreak, place a rock near the xenia and they will move. Sometimes under good water and light they will simply split down the middle themselves. I have also found xenia will grow up toward the light.
Zoos should grow pretty easily too, I've heard that aiming a power head at them will get them to grow with the current, though I havent ever tried it. I guess you dont want to cut Zoos without somesort of gloves on, they can be toxic.
As for the purple mushrooms, I got one from my cousin, and now they are carpeting my tank. Some are huge, 3-4" across!They are actually encroaching on and beating up some of my ricordea now, so im going to have to "harvest" some to avoid them killing everything. Xenia are cool, but be careful with the purples mushrooms. They may take over everything!