Question: New Newt Tank help?

[fromthepuggle]

I have several sword-tails (c.e. ensicauda) arriving next week, and I want to have a happy home ready for them! I had orientalis as a kid, but realizing in hindsight had no idea what I was doing, and now that I'm an adult, want to do this right, but realizing I'm a total noob. I've been searching the forum, the care sheet on the species, the basic FAQ, and still have some ques, not finding easy answers, or lots of contradictory advice. So far I feel like I understand what to do with substrate options (no gravel except under thick layer of sand or aquarium soil), temperature, water/land ratio 70 percent water to 30 percent land, avoid strong currents from filter), lid (need a good one), light (keep away from window, otherwise tank light optional). But still some questions.

1) Do I need to sterilize rocks/wood that are sold by petstore/amazon specifically for aquariums?
2) do I need water/stuff from an old tank to get cycling going? how does cycling relate to filtering, I'm guessing I want both going?
3) how smooth do rocks need to be to be newt safe? Is slate generally ok?
4) cleanup crew? are they more trouble than they're worth? ghost shrimp? snails (ramshorn, apple, others?)
5) how long should I let my new home settle before putting the new newts in?
6) best practices rule of thumb for filter/poop cleaning?
7) size. I'm debating between 29 gallon vs 40 gallon for five ensicauda ensicauda. Thoughts?

Thanks in advance for any input!