Hi Cap! Ignoring the platform stuff, here's my thoughts:
1.) my first immediate gripe is a UI complaint: when facing a brand-new event with a bunch of tiers and a number in parentheses on the battle button showing how many attempts I get, it's not immediately clear whether this is an event where I can do each tier that many times (as is the case, it turns out) or whether it's a credit heist/droid smuggling type situation where my attempts are a total across all tiers and it makes sense to only do the highest tier I can try. Wish there was a better way to make that clear.
2.) I liked borrowing the guy to try him out. Very fun, great way to introduce a new character! Plus you did a nice job of making the event where his abilities were useful so he really got a chance to shine. But from looking at his stats it appears all his abilities are level 1! I think it would make sense to have the K-2 you borrow at each tier of the battle have roughly appropriate gear and ability levels for that tier, we'd get a better sense of how his development progresses and how he plays at different levels resource investment into the character.
3.) I really like that by the end of the event we can potentially have him maxed out. Very preferable to the Scarif Rebel Pathfinder and Bistan events, where I got them to ~3 stars and still have a ton of work to do to get them actually usable (not to mention, having never gotten to borrow a maxed version, I'm not really sure how usable they'll ultimately be) so they've just been collecting dust since then.
4.) I don't have too many comments on the actual fight mechanics because I was running Emperor Palpatine and Royal Guard and mostly the enemies were stunned and slowed and shocked and did not get to take very many turns, but the final wave of the last tier was pretty challenging, and forced me to think about who to target and when and with what, without being tear-your-hair-out difficult or just being a "repeat until the RNG loves you" type of fight, so from what I saw I'd say you did an excellent job there.
5.) I like that K-2's kit is good for this fight, although he doesn't mesh well with certain other characters (Stormtrooper Han, for example). I liked how in the fight descriptions you offered some tips about the bad guys; maybe offer some tips about how to get the most mileage out of the new character, as well?
6.) Nitpick: one of the tips talks about Magmatroopers' Thermal Imploder AoE reducing turn meter, but I believe the guys lobbing that AoE at me were actually Sandtroopers, even if the ability is the same (and has the same animation and sound effect and everything). Might confuse some folks.
Anyways, great event, exclusivity issues aside. Hope we'll see some more like it that are open to everyone on every type of phone.