Trade bans can be checked with the GetPlayerBans WebAPI method.
Escrow can be checked with the GetTradeHoldDurations WebAPI method.
getUserDetails() works by loading the tradeoffer page (using the user's trade link) and scraping the results from the HTML.
You're far more than one step away. Joining a community server is not supported and never will be, as you'd have to implement VAC which nobody has been insane enough to try.