I'm playing Turkey and want to make my first 40 width division template...
Is it best to get my division numbers up first or finish the template asap?
It depends on what you want to optimize for. Deploying a bunch of divisions and changing their template only later can be the better option if you need an army right now. It does not have any real benefit for the division design process itself.
If you want to minimize equipment lost from exercising while not spending additional army XP, you should fill in the battalions with high manpower and low equipment attrition cost first (i.e. infantry or motorized). Training those up to regular level is relatively cheap and adding the remaining battalions and support companies later on will not dilute the XP level very much due to the relatively low amount of added manpower (experience is tied to manpower, not battalions). As a result the exercise time with the expensive equipment will be shorter. Note that
equipment types with low counts (like artillery only from support artillery or support equipment only from recon company) are also expensive for the purpose of exercise attrition.
If army XP are not a concern, you can take the previous approach one step further and design pure-infantry divisions with the right manpower. Exercise those for cheap and then switch them over to the final template for a head-start in XP.
Can the A.I have rebellions?
I'm playing as Free France and I've been trying to cause a rebellion in German-occupied France using National Focuses and spies. I've got a region to 100% resistance but nothing happens.
A rebellion is not based on an individual state:
Note how the icon for rebellion is in the top right, where it shows the average resistance of
all Algerian states. This is different than the other resistance effects like "Emboldened Resistance" and "Uprising" below, attached to each individual state. You'll need an average resistance of 90% across all French states occupied by Germany.