For Phoenix, the only 2 that I have above G8 are the 2 Jedi & only Ezra was over 8 when I did 7* Thrawn.
It was Ezra 10 & the rest like 8+2-4 pieces.
Take all abilities to 7.
Take Uniques to Omega.
Also Omega the basics for Zeb & Ezra.
Other than that your actually further w/ them than I was in a lot of ways.
As for who to go after, there really isn't a Legendary character in the game that you DON'T want.
All of the event characters are useful.
I would focus on those that you have closest to getting as well as those that require less gear.
For my order, 2 years ago, it was something like......... Palpatine, Yoda, Thrawn, BB8, R2, Revan, CLS, Chewie, Drevan, 3PO, Rey-JT..... all in the first year.
Year 2 was basically Malak & LOTS of gearing all the above up to actual useful levels.
This weekend is my 2-year anniversary and I'm ready for GAS except for Negotiator, need a couple months of Get-2 coins still to finish it.
Finally, a guild, if you have GEO's ready for Wat Shards & several DS G12+ teams, shoot for a guild doing DS-Geo & LS-Hoth. (That is what mine is doing)
If you can't actually help out with the GEOs & lack gear for at least 4 full DS teams, then go with DS/LS both on Hoth.
The GET-1 will be useful to bank for Malak, GAS, Hoda, & Wampa, as well as STUNGUNS.