You'll be fine. It's on one of the most secluded beaches on the entire island. Is it busy? Well, that's relative I suppose--during the day you'll get some foot traffic from locals from the gypsy village next to the beach, but it's not like the rest of Phi Phi where you've got pasty tourists drinking whiskey buckets and puking all night. It wouldn't be something I'd classify as 'crowded'...more like 'local'

Mosquitoes? If you don't want those, then you probably shouldn't be on any island in Thailand. They're attracted to wet places...so on most every island they come out at night. Bring DEET with you and you'll never even notice them.

Zeavola is one of the most unique and beautiful hotels I've seen...and Laem Thong (the beach it's on) is unparalleled in scenery and for off-shore snorkeling.

You'd be mad to cancel...just my 2 cents.