Current spirits:
Bound: F3 Spirit of Air with Guard as the optional power. Current active powers are Concealment, Movement, and Guard. 6 remaining services.
Unbound: F6 water spirit with Binding and Weather Control as optional powers. Currently only using Weather Control, I believe. 3 remaining services.
Illeana can game the system a bit by issuing orders to the Unbound Water spirit that will remain in effect even as remote services. Such as "Maintain the Movement power on James until sundown," etc.
The Movement power is restricted to the environment controlled by the spirit, so if James is swimming the water spirit will still need to use Movement even though the air spirit is already sustaining the power.
Guard doesn't seem to have environmental restrictions. Thus the air spirit can use the Guard power to prevent James from drowning, which is one of the explicit examples in the book. That said, every individual use of the power counts as a service, so it could (in theory) chew up services quickly if James finds himself in a pinch.
The water spirit might as well use Concealment too, since it's more powerful than the air spirit's. I'm not sure there's a good candidate for the water spirit's fourth service. "Protect James" is too opened-ended.
That leaves us with:
F3 Air Spirit (6 remaining services)
Concealment, Movement, and Guard
F6 Water Spirit (1 remaining service)
Concealment, Movement, Weather Control
Illeana isn't thrilled about the prospect of James swimming around in the swamp, but James is a big boy and she's not going to stop him. Plus she can give him some spirits and preparations to help even the odds.
To answer your questions:
1) James cannot jump from island to island or tree to tree.
2) James can swim, either on the surface or underwater with his air tank. Illeana would prefer not to cast and sustain Oxygenate as she needs her concentration for the conversation with the witch (and she's already sustaining a spell to alleviate her allergy to wood, which is important in the mud hut made out of vines and branches.)
Swimming is viable, although with some meaningful risks. Visibility underwater is maybe 1 meter, either thermographically or via normal vision. Concealment is powerful but not invisibility. As a base swimming rate, James can swim 9.5 meters per turn, 190 meters/minute, 11.4 km/hour. With the spirit's movement power added in, he can really motor along. That said, it still requires effort. James will need to make a Fatigue test every 3 minutes. The first test will be 1S, the second test 2S, the third test 3S and so on until he rests and resets. He will soak Fatigue with Body 5 + Willpower 7. Granted James can swim pretty far in 3 minutes at the above speeds, but all the Concealment and Ruthenium Polymer Coating in the world won't conceal the wake he kicks up swimming at 42mph.
If the spirits are disrupted, James is in trouble. If they run into a mana ebb or surge, things could get interesting. Given that it's summer and light out late, we'll say that James has about 8 hours until sundown and the departure of the water spirit.
Wireless bonuses, let's say that everything is eligible but the smartlink. This will make James noticeable to anyone scanning for devices. He can run silent with this Stealth dongle, but it's reasonable to presume that smugglers will have defenses in place to be on the lookout for approaching devices, which they will likely equate to non-friendly sources (especially if said devices are running silently).