not actually having done it, just peculation, but...
give the vehicle a new cargo hold abilty for only one person (or 2 or 3 or 4, depending on what you want), and the associated load and unload abilities. I don't see what would really be so hard about that.
As for the smoke gren thing, a series of triggers like so (done without world edit):
SmokeGren
Event: -A unit begins the effect of an ability
Conditions: -Ability being cast equal to Smoke Gren
Actions: -Create a region centred on target point of ability being cast of height 200 and width 200 (or similar, not sure how the action really reads)
-Set SmokeGren=Last created region
-Add to EnterSmokeGren.gen the event 'A unit enters SmokeGren'
-Add to LeaveSmokeGren.gen the event 'A unit leaves SmokeGren'
EnterSmokeGren
Event: -
Conditions: - Whatever you want
Actions: -Give entering unit the ability Invisible
LeaveSmokeGren
Event: -
Conditions: - Whatever you want
Actions: -Remove Invisible from leaving unit
umm that might work... i dont have much luck with triggered spells on the first time round tho... usually takes me the better part of a week to do it right (big confidence boost for you
)
Bort