Q1: forget it. Unless you have enough money and are keeping really sensitive fish, don't bother. You can always take water the the lfs and they will test it (if you really need to). I have never tested my water (ph only) and never had any problems.
Q2: water changes wouldn't hurt, but only do small ones. As most of the bacteria will be growing in the filter, changing small amounts of water and cleaning up the rubbish wont harm (i think)
Q3: Siphoning, You don't need to be too [insert correct word here(perfectionist?)] about it, the plants should use it up if you have enough. You can suck up most of the stuff sitting on top of the gravel by holding the hose a few cms above the substrate.
As for too many neons, Don't worry. I've barely given my tank time to cycle before I put in discus and everyone was fine. I think its a bit over-exaggerated, but then again, "what works for you, doesn't always work for others".