Hello and welcome
I LIVE for hitchers!!!! Its sooo much fun to see what pops out! Whenever I get a new piece of
live rock, I spend days just gazing, looking for something. Sometimes I am pleasantly surprised and sometimes alarmed!
Your 'plants' are
macro algae I think. The one in front looks like it could be halimeda, the pink one in the back, I had at one time and really loved it, it didnt survive my low lighting at the time, I was disappointed. I dont remember the name, but it should be easy to look up. Maybe someone else remembers the name

I am not familiar with the stick-looking ones though.
I had several large bivalves (clam-type) that came attached to my
live rock, they were very hardy, and I had them for a long time, but I eventually lost a few and I think it is because I now run at a higher temp than I did before going reef.
Maybe someone can help with your crab, Ive had similar ones hitch in, I didnt worry much about them then because I really didnt keep anything that they could bother at that time
