Good to hear that he's getting used to you.He is getting more curious with his surroundings and seems to want to get out and explore, but I want him to be a little more calm before I let him out.
Yes, better let him settle down a little more before letting him explore.
Not sure if he's up to meeting the other cats yet and make sure if you let him explore, make sure the other cats are not around him.
If the other cats are not around him or are kept out, open the cage door and let him cone out on his own. If he feels safe to come out, he will come out and also you can have a cardboard box and lay it on it's side so that it'll be an extra place for him to retreat to and a cardboard box is safer than a cage as it has no hard sides just in case he bangs around if he panics.