We did a month down in Panama with a Jungle Operations Training Center rotation attached to 2/75 Ranger Bn back in 1997.
It was a lot of fun for us, but it was a suckfest for the hooahs.
100% ripstop BDUs are nice, but wear off really fast with the rain and hard use.
50/50 NYCO holds up well, but it's hotter.
I actually wore Tigerstripe for most of that deployment, other than when we were in admin mode at Fort Sherman and had to be in BDUs, but we had relaxed uniform with BDU bottoms, jungles, brown T-shirts, PCs, and Camelbaks.
Most of the time we were in the jungle doing ambushes, site security for simulated weapons/drug caches, or OPFOR in MOUT.
In the summer in the Arctic, the conditions are similar, with tons of humidity, more mosquitoes, but none of the exotic plant and animal life you have around the equator. Panama had some interesting animal life for sure, between bats, gators, and howler monkeys.
There is a natural fiber that comes from a particular wood that is extremely fire-resistant. If you burn even one of the small fibers, it looks like a tungsten filament in a lightbulb when brought into contact with direct flame.
I would use that with an engineered fabric microscopic structure designed to shed heat and support evaporation.
Working in the jungle isn't that terribly worse than deciduous woods in high humidity, but does have some plant life and precipitation cycles that are unusual.
Black palm, sharp leaves in other PACOM, SOUTHCOM, and AFRICOM regions and daily rain make it more difficult to conduct dismounted operations, but we've done it before. We do need at least one JOTC in the tropics to replace Fort Sherman. Hawaii is not a good representation of that.
Maybe a joint-UK training center could be established with their place in Belize.