I'm in the U.K,
I got my panther from Gumtree, He was a young adult and have been very well handled so is just about the most relaxed chameleon I have ever seen, There are a lot of ads with ex pets- choose carefully and find a loved and healthy animal you might be lucky and get one that is as super cool and relaxed as mine. I also got a baby jacksons and watching them grow is a very wonderful experience but he's ungraded his vivs 3 times already and not yet finished-lol. If I had to choose I'd go advert again- he's been great. and I knew the size he was and could buy without thinking of upgrades. The momenet I bought him home he was relaxed and not stressed and eating within hours so I don't see any problem of one not getting to know you.
I have a mesh cage that I housed a false chameleon in for a while but unless this house,( or your house?) which is not a warm house is super warm, the cage always seemed cold and draughty and difficult to keep the basking temp right and the humidity too, so I dont use it now.
I have a juv Jacksons in a large exoterra but he will need larger when he's full grown,
My panther is in the largest arboreal vivexotic-4ft long-3ft high- it's a good size for him, It keeps the heat in well, i cut four holes in the sides for better ventilation and covered them with large plastic vents- there is a large garden plastic tray that covers the base, i have live plants sitting in the tray that soak up most or all of the water during the day ( I probably will drill a hole and and fit a drain and have a bucket underneath for better drainage soon) His heat lamp is a round one that sits in a hole cut in the top and protected by a mesh cage- he has a dripper via another small hole drilled in the top- I feel that for me it works very well. I also have two that we made- a wooden frame with polycarbonate sheet sides, mesh top and sliding glass fronts that work for the climate here.
Good luck in finding your chamelon