Note that for most of North Africa, you won't need a HQ, as at least two of Algeria, Tunisia, and Morocco are just minor countries, and the CW may freely enter them. (But not CW TERR or minor country units.) If you made some other country the new French home country, you can enter all three freely.
Also note how FTC works: You need a HQ to get units to enter a country. Once the units enter the country, the HQ can leave, and the units that already there can stay there. Of course, if they are destroyed, you need to bring an HQ back to get new units in there.
A major power or minor country unit that ends any step in the home country of a friendly major power it doesn’t co-operate with is destroyed unless:
It started the step there; or
It started the step elsewhere and the unit satisfies the foreign troop commitment limit.
Thus it is legal to move units in, using FTC, and later move the HQ out, since the other units "started the step there."
I thought I knew how to play this game....