Thank you all for your responses.

FS does provide a kids club which would allow our boys to play with other kids. However when we were in FS Langkawi, there were hardly any kids there (perhaps for an hour at most on the 5 days we were there). That's one of the reason I thought of Aman. Also the list of children activities they've just sent me seems suitable for our boys. The boys are generally well behaved and not rowdy and I'm intrigued about Aman (given the reviews on FT).
Interestingly when I emailed FS Jimbaran Bay about accomodation options, they only advised me about booking 2 one bedroom villas and not the 2 bedroom villa (even though they are available on our dates according to website). They are also very slow in responding whereas Aman's response is prompt.
Thanks for the offer to PM Ericka and Musken - will certainly do that after the festive season is over.
Happy holidays everybody!