I think it is pretty much any thing that occurs in the deployment phase is "during deployment"
Also, (I haven't checked) but I don't think a unit can join an IC, the IC has to do the joining.
The IC joins the unit by being deployed within 2" of a unit, ending his move within 2" of a unit, or being declared joined to a unit when they are both in reserves. When I said Vice Versa, I meant that instead of an Independent Character joining a unit with Infiltrate, you have an Independent Character with Infiltrate join a regular unit.
"Trying to make some sense of it all,
When I can see it makes no sense at all"
"Fools to the left of me,
Jokers to the right,
Here I am,
Stuck in the middle with you."