First of all, look around the map for CheckPoint Switchez
(CPS).'Colonel Gromiell'
might occasionally choose to blow up 
thingz, but preferz his Gauntletz 
.'Captain Crater'
only likez to fill in Holez 
and dig up Moundz 
.'Talc'
never goez anywhere unarmed!'Graniel'
is a born experimenter ... he'll try anything once 
(or twice ) 
.'A. Nony Mouse'
has amnesia ... he'll follow any order unconditionally! 
Start with Grunt #2 (Talc) and when the Grunt you have currently selected seemz to be 'stuck', see what some other Grunt can do. I (GooRoo) used Talc twice, then Crater three timez, then Graniel three timez and finally Gromiell five timez on the first island.
I left Talc behind (temporarily) and moved the other three to island number two.
You should be able to take it from there, for the remaining twelve islandz.