In general, I'd go for the basement. Low 60s ambient temp usually works well for ale yeasts (there are exceptions to this rule). The dehumidifier shouldn't cause problems. Might dry out your airlock quicker, but you can always top that off.
For your first, the amber in the kit should work out well. Also look for the Dead Ringer kit (should be like Bells 2 hearted). The Sierra Nevada clone is called Sierra Madre, iirc.
The hoegaarden clone isn't too difficult. A few extra things to throw in at flameout (orange peel and coriander). The instructions on all NBs kits say to use a secondary, but you could skip it on most beer. Tons of topics on here about secondary, so read up and decide for yourself.
Cleaner and sanitizer- I use PBW and Star-San. You could use fragrance free oxy-clean from the store instead of PBW. I don't know of a homegrown sanitizer, though. Star-San is light... it ships as a small bottle of concentrate that you mix with water. 1 Oz of concentrate makes 5 gallons of sanitizer, and you can save it between batches, so a little goes a long way.
Do you have a local homebrew store in Bermuda? Might be worth looking into.