i would say yes, it is safe t put into your tank. make sure you get all the dead organic matter (DOM) off of it by rinsing it off and maybe setting it out in the sun for a bit.
as for the maroons, i think it just depends on what other fish you put in with it. my dad has one that is super cool and doesnt bother anything. i have seen others that are the same way, but i have read that they can be aggressive as well..