Let me start by saying HOLY POWER CREEP BATMAN!
The Elite Wing Guard are the new kings on the block.
They are flat out better than Elite Stormtroopers.
I think the regular ones are fairly balanced but the elites take the 9pt efficiency to a whole new level.
Same damage output with rerolls as eStormies. Same Health and Speed. Extra Guardian Keyword for free. And recover 2 instead of accuracy 3.
I guess this one is personal opinion but I hardly ever use the accuracy surge on stormtroopers. They are tough enough and come back with reinforcements. They don't need to be taking shots at long range and wasting surges that could otherwise be 2 damage. These guys are the same, but you now get the option of doing less damage and healing.
Its basically a better heal than snowtroopers, just as easy to use, and doesn't take a separate action, which means it doesn't affect your damage output as much.
The guardian keyword also gives them access to Guardian Stance and Bodyguard which is handy with the squishy expensive merc units like Trandos and HKs.
I consider the strain ability as a bonus. Nothing special to write home about, but still handy. It's basically an offensive version of the Royal Guard's ability.
Could be super annoying if you block LOS with junk droids or hired guns forcing your opponent to take strain when attacking.
If used well, it's much more useful than a few focus tokens from dying like the Stormtroopers get.
The Ugnaught Tinkerer seems like pretty good filler for 3pts. I don't think the elite version is worth the extra 2 points.
Having the junk droid sit on objectives, terminals, open doors etc is pretty good... it basically gives you some extra free actions.
We don't know exactly what the limitations are for Companions just yet, but seems like it's worth the low cost.