I've had the same questions before, and wasn't able to come up with any official answers. Here are my best guesses though and how I would run it.
1) Yes, Levy forces require logistics. Logistics isn't about payment of the troops themselves (that's their maintain cost, which levy's don't have). Logistics are needed to provide food, set up camp, keep people organized, ect.
2) No, just because it seems like double dipping on the cost of mercenaries. The purpose of hiring mercenaries is to avoid having to pay Raise costs, but with increased logistics a lot of those savings go to buying more logistics strength. This seems major enough that if it was intended, it would have been mentioned.
That said, I wasn't satisfied with how mass combat handles logistics anyway. It feels
far too simplified and makes too many assumptions about how your forces are operating. For example, a Roman legion would need the same amount of logistics support while stationed inside Rome itself as it would while marching around the northern coast of Europe. If you do the math, it's also cheaper to not provide any logistics to a force and retrain them as they starve to death.
So I decided to rewrite the rules, keeping the concept of LS, but basing the LS requirements of a force on a few different factors. I introduced two new factors, "Distance from Supporting City" and "Speed of Movement". The full rules are detailed here:
https://the-fall-of-brekhan.obsidian...mbat-logistics
It's worked well in practice so far, and does a much better job of letting you detail the cost of troops garrisoned in cities or redeploying through friendly territory. The math wasn't super difficult, but it was annoying enough to do on the fly that I wrote a spreadsheet to do it automatically (Save a copy for yourself to use. Fill in the light grey boxes with information, results are presented in the dark grey boxes):
https://docs.google.com/spreadsheets...it?usp=sharing
Here's what it looks like in practice with our army, currently garrisoned at a mine near the supporting town "Glumtown":
https://docs.google.com/spreadsheets...it?usp=sharing