For wires, whether you stick with aluminum or go with copper, make sure they're sized properly. Most electricians I've seen in India will undersize the wire and this causes the wire to melt in the wall. Same reason it's always "when the wire melts" not "IF".

I always recommend a wire that's one gauge (or thickness level so .5-1.0mm in your case) thicker than needed for the breaker size. This way if there's an issue the breaker will trip and wire won't overheat/melt.

Moisture, there's a solution there too. Sent you a PM.