Our local comp plays a home & away system, so is at the mercy of the various clubs' venues for lighting, ceiling height, flooring, whether there are surrounds for each table etc. We play where we can. The opposing captains are jointly the referee. Occasionally the player umpiring will call a let & explain a problem with a particular serve. It seems that it is a tacit no-no to fault a dodgy serve. This doesn't help when your team consistes of a state umpire, international referee & state secretary

The ITTF rules are followed with exceptions that are listed on the local association's web site or on the draw sheet: no expedite, no timeouts, rules regarding full or partial forfeits for no show, time limits for finishing at particular clubs, off the top of my head.
As far as local tournaments go, both main venues have reasonably good conditions re lighting, ceiling, lighting, surrounds. As far as officials are concerned, referees & umpires are charged for by the local Umpire's association (which then recompenses them, sometimes at a loss) to the organization holding the tournament. It is up to the organizer to request umpires. Unfortunately both officials are recompensed with petrol money & occasionally meal vouchers. It is very much a voluntary thing for an accredited umpire to turn up to a tournament specifically to umpire & not play or coach or parent. Even the AOQT & OOQT paid only meal vouchers (& kudos of course), and hence had some state level umpires officating, not all national (for the AOQT) or international (for the OOQT).