Hello Adi!
Wha..hahaha....your question is longer than our reply! Kekeke...that's a good sign though! It means you really take your this HM Seriously!
Mish is absolutely right abt it! If you're able to squeeze ur travel period within Oct or even end oct, there's lots of free nites thingy around!.
All the resort you've mention should be quite safe, i.e Hilton, Anantara, Mirihi etc....
There's a question for you too, cos diff ppl diff objective for their HM. For me, now a "Cheapo"

traveller, I want VALUE!!

That means more days in a water villa at the lowest possible rates. Let you choose between 2 below, for the same rates, which wld you go?
1)3D2N in a ultra posh resort such as Huvafenfushi, W-hotel or O&O reethi Rah
2)8D7N in a normal beach villa/water villa such as Mirihi?
For S$8K, you've lots of choices for Posh/luxury ones but you'll stay less days loh!
ANW forget about crown tours, they charge fees for using Credit card. As for Mal-dives.com, ok lah, once you know how to handle them shld be no prob.
Forget abt Full-board. I always advise ppl(Although it's really diff ppl diff preference loh). Buffet got lots of food, and some of them you didn't even hv chance to touch.
Go Ala-carte feels better for me...cos it saves me money, as their portion is big, and I spent it on other things like Spa, excursion etc...
Don't worried even if you decided to choose Buffet(full-board) cos you'll not see those typical Singaporean type of Havoc! (familiar scene in Malaysia resort or even in SGP buffet rest.) Most ppl in Maldives are the staff and ANG-MO from europe.
Generally, I rate Mirihi's steak/lamb chop better than Hilton's one, but Hilton got nicer Spagetti and much more food in the menu.
Just for your info, most mid high-end resort like Hilton are increasing their rates by a huge margin by next year, it's still a choice to visit them this year, else as years goes by, really, they're gonna be in the same league(rates for all villa) as O&O, Huvafen, four season etc..
Reason is that they're going to extend their some exclusive service to all villa types, i.e free buggy ride from pt to pt, TV in the rooms for all etc..
Hope it helps.