Adverse Possession is exceedingly, exceedingly tricky.
Not to be too blunt, but YOU are asking others to take a HUGE risk on something you do not appear to be expert upon, but are proposing be sucessfully performed by the grace of luck.
What YOU need to do is go out NOW & BEGIN the process which will establish color of title, chain of title, and the date at which your claims began.
Also,how are you proposing this title be taken?
In your personal name or that of a foundation or some such?
You said PURCHASE in your original post NOT squat without title,so your first post us effectively *false*.
Why would you say something like that, then change the fucking conditions??
If not outrightly sketchy, def outrightly foolish & indicative of inexperience.
I'm not upset over the proposal of squatting, but you said purchase, and then squat, and then.. then.. that these islands are worth millions..
I'm not saying it isn't possible, but do stuff in the right order..
1) begin to establish your claim.
Find precedent & requirements..
Get KNOWLEDGE, not just ideas.
2) do some searching on current arial and satellite imagery.
Look at tax roles.
Don't explore blindly, but get some viable targets together
3) in the US there are deeds known as "quitclaims" which hold no actual authority of title, unless executed by actual property owners, but can otherwise be used to document at least the actual date where begins the "open, notorious and adversarial" possessing of a piece of property against the established title which holds it.
Adverse possession rests primarily upon beieng able to demonstrate that a property is intentionally abandoned, or unable to be utilized as title to it may mandate.
In the US you *cannot* AP against title held by government.
Make sure none of the properties you are suggesting are held by the state.
You aren't going to get stuff just because you want it, so before organizing a flotilla or whatnot, that you *HAVE A PLAN*.
Just throwing money and wishfull thinking at crap is the fastest and easiest way to fail.