I do like that pic as well.
Okay onto the advice!
1. How well does A Time of War play compared to Pathfinder obvious differences aside (D6s v D20s)?
In A Time of War, if you are in combat then either you messed up or are in a position to ambush someone.
Combat can be very lethal with it ending in one or two gun shots assuming the person's armor doesn't hold.
Which is why I've always seen it more for roleplaying than personal combat, but AToW Companion DOES have optional rules for "heroic mode". Meaning it buffs up the health points, makes healing easier, etc.
Perhaps a few tweaks with that will make it more run and gun.
2. How quickly do new players pick it up?
If the GM can tell a story, not too bad. My group played with the quick start rules a few times and we were okay with it.
A point of advice, use character point creation first instead of the life module.
That way people can get what they want without wondering if the life modules will provide in the end.
3. How easy is it for someone to GM?
Aside from Tactical Armor rules, or whatever they use for Battle Armor, the rest isn't too bad.
A good GM will make or break the session really.
4. A Time of War has a lot of "monster" stats in the back of the handbooks. What about NPCs? Is there a good database for that similar to Pathfinder?
AToW and the Companion have generic enough stats for skinning on what most games use.
The low level, the higher up guy, the big boss, etc.
Also don't forget Lance Dossiers and other electronic releases from CGL which actually offer character sheets.
Maybe if you like that person, you could use them (or kill them).
5. Overall thoughts of the system?
Aside from that whole "mods to the dice instead of the TN" thing, I don't have much gripes on it.
6. We are playing a late Succession Wars game just before the end of the 3rd SW. Any tips or advice that I should look out for?
You'll need to tweak it until something for that timeframe comes along. Personally I'd take the Era Report 3052 and tweak it a bit since that runs the 3039 - 3052 time frame, which is the closest based on existing releases.
7. Tips and tricks for a veteran player, but relatively novice GM are appreciated.
I'll 'borrow' from Acolyte's advice, but tweak it a bit. If you don't have stats, assume the value is a 6 for an attribute. That's the rule of thumb from the books last I read, or at least the Quick Start.
Sit down, have fun, don't worry about what's canon and just carve out your own stories for the group.
8. How do you choose to incorporate 'mech-scale combat? Total Warfare or Alpha Strike?
Duels: Total Warfare.
No way am I using the Tactical Combat ruling, unless someone
REALLY wants that Solaris itch.
Normal fighting: Alpha Strike, where the Mech Unit's pilot gets "killed off for real" if I do a roll of under 10 or so. Something like that.