@Skywalkerr
What I've done since :
I now have JTR 7* G8 All skills max (Except zeta)
I unlocked Asajj 3* (24/30)
HRS Upgraded him to 4* (28/65)
I zeta Han, CLS IBAT and R2D2 Number Crunch
This is great stuff!
You'll want to zeta JTR's leadership pretty quickly, and all of her zeta abilities are going to be needed eventually. (I did Virtuous Protector 2nd and Insight last, but other people did Insight 2nd - either way is okay so long as you get them all eventually). You can hold off on that first zeta for just a bit though. You want to give more gear to your Rebels first, and then you can gear up Resistance if you don't have another immediate priority at that point. Once you have JTR, Scav Rey, Finn, and BB-8 all at least up to g9 along with any one of the following: Resistance Trooper, Poe, Resistance Hero Finn, Resistance Hero Poe, then it's time to prioritize JTR's zetas and make the Resistance toons you have into a real team.
Make sure to give HRScout all Crit Chance mods (Three sets of 2 mods each). Don't worry very much about speed on HRScout. Scout gains tons of turn meter. (At your level where fast mods are precious, +45 to +60 is about all you should be giving to Scout, and +30 of that will be a speed arrow.) Worry more about sending Crit Chance through the roof. Later on you're going to be using Scout with Chewbacca, and it's going to be an amazing combination. Scout still doesn't have a good enough kit to be used in Arena or other places if you're not fighting Empire, but Hoth TB is nothing but empire opponents and Scout will knock them down like crazy. I never gave my scout better than Gear9, that way he was always the Weakest (Chewbacca assists the weakest ally) and his extra turns gave Chewbacca tons of extra assist attacks without using up valuable High Speed mods. This is most useful on the couple of missions where Scout is required, but it works anywhere in Hoth TB. (If it's not a rebel only mission and does not require HRScout, you can always use Grand Master Yoda as your weakest ally for Chewbacca - he gets tons of TM as well).
I will unlock General Kenobi the next time we do a tank event. (Should I start upgrading him right away) or wait until he's 7*?
It really depends on so many things, where you are with other gearing, etc. Me, I generally don't start gearing people until they hit 6*, so then they're geared to a useful level when they hit 7* but I'm not wasting gear on 3/4/5 star toons who can't use it for a long time. If you start early enough so that you're just hitting g10+4 to g11+4 when you get that 7th star, you probably did it right.
But again, that's me. You can play different if you want.
Rebel Officer Leai worth getting shards?
You should only be getting her shards from the Hoth Territory Battle special mission. Don't buy them.
You want to get her up to 7* for the day 6 special mission in Hoth TB, but you won't use her much once you start playing Geonosis TB. That day 6 special mission is difficult, and it requires ROLO (Rebel Officer Leia Organa) as your leader, but you can get some really great light side toons that will eventually stomp this thing without too much effort, even at g11-g12. So I wouldn't gear ROLO past g9 (I geared mine to g10+2 and kinda regret it). Heck, you might not need to gear her at all, just level her up so you can max out her leadership - the leadership bonus continues after she dies. But if she's not 7* you can't even enter the event. So play to win that special mission that gives ROLO shards, but don't worry too much other than that. I would at least try to play the day 6 mission with a gear1 Leia before dropping gear on her. If your LS Toons are powerful enough by the time you have her 7*, Leia dying on the first hit won't matter. If they're not, I still wouldn't take her past g7 unless you don't have any other gear priorities when the time comes. Definitely DO NOT gear her up until after she hits 7* and you've tried that day 6 special mission against the AT/ST.
I looked at my caracthers.
I have the gear to upgrade Ahsoka to G9 or Grevious to G10
I have the gear to upgrade Boba to G9 or Ackbar to G8
Which one would you upgrade first?
Ahsoka over Grievous. (You need to advance in fleet right now more than you need Grievous, who requires good droids around him to make him great - and those are a long way off).
Ackbar over Boba. You're trying to get your fleet together and Ackbar is more important for that than Boba. Boba is also already at the gear needed for your other basic Bounty Hunter and DarkSide Fleet needs right now (like the Credit Heist and Zeta Mat challenge). It's not that you don't want to take Boba to g12, just that Ackbar comes first in the scenario you're working on.
Ackbar Ship (is there an ability more important than others?)
The AoE attack (Defiant Volley) first. Band Together second. Master Plan Third. Seize the Advantage 4th. The basic attack is last.