I'm not a wood expert per, but I can recommend:
-You can clean the mold with a soft tooth brush.
-I don't think you can damage the bass with over-waxing, but I don't know if doing it would give you extra protection from the high humidity. Waxing lightly every 3 months or so should be plenty either way.
-Buy a humidity meter. They are cheap and well worth it. You want humidity to be at 50%, and usually not over 60% and not under 40%. I live in Florida, so I run the A/C almost all year long and the A/C keep humidity at a steady 50% all day long.
-If you are getting humidity over 60% all the time, then maybe investing in a dehumidifier for the room could be a good call, and run it a few times a week.
-Wenge and Ovagkol and pretty hard woods that should resist a great deal of humidity, so unless the room is at 80% humidity all the time, I don't think you run the risk of the glue melting and joints coming apart.
-If buying a dehumidifier is not practical or too expensive, maybe try one of these: http://www.amazon.com/Davis-Instruments-Air-Dryr-1000-Dryer/dp/B0014TMXVA and put it in the room, not too close to the instruments.
Laminated necks tend to move either way, but you feel it more when the necks are unfinished. . . I've even experience this with brand new basses not subject to whether changes, so it's not a big deal.
And, I'd normally recommend treating the necks with Tung Oil to give them "some" protection, but wenge really doens't need to be finished, unless you live in the jungle and really need hard protection, in which case you could apply coats of poly finish. But not in your case.
I repeat, I'm not an expert. . . I'm sure Warwick users here can chime in.