I am new here (aside from lurking)... but I wanted to chime in!
Regarding the batteries first-
I have owned an X100T, I now own an X-T2 and an X100F. I have, in the past, used third party batteries quite a bit. Honestly, the performance/cost was always very acceptable to me. When I am out shooting a lot (or traveling) I tend to pack a few of my third party batteries as emergency backups. All of the third party batteries that I have used have had a habit of not accurately reporting the battery level; they would go from near-full to empty inside of 5 minutes.
All of that said, be very careful using third party batteries, especially if you plan on shooting 4k video.
A few months back, my camera went completely haywire, it was like the shutter was stuck between open and shut and couldn't make up its mind on where to go. I couldn't power the camera off. I went to pull the battery (a well reviewed third party brand) only to find that the battery had swelled significantly in the camera. It took a pair of butter knives to pry the battery out. Thankfully, there haven't appeared to be any lasting effects.
It is my understanding that the new NP-W126S batteries are designed with heat management and provisions for rapid charge/discharge. The X-T2 does generate a lot of heat when shooting, especially when shooting 4K. I think my problem was compounded by using the battery grip which charges the batteries at a much faster rate than the standard charger. I still occasionally use the third party batteries, but never for video and never in the battery grip.
Now for the rest of your questions...
1. I have Lexar class 10 UHS II card that works fine. I have managed to store quite a bit of 4K footage. As far as the 30-minute 4k recording time goes, I believe that you still need the battery grip (in addition to a good memory card) in order to record a full 30 minutes of 4K in one go. Also, be aware the camera does warm up quite a bit in that time.
2. Lightroom and ACR work OK. The way that Adobe handles fuji raw definitely leaves a bit to be desired. I recently migrated away from adobe and I have not 100% found a workflow to replace it. I honestly run with my near-sooc jpegs more often than not. Capture One is pricey but is so far the best contender to replace LR in my book. No Fuji profiles - but the color handling is awesome and the IQ seems really good overall. I have also heard a lot of good things about Iridient Developer+Lightroom for the best IQ. From what I have seen, the IQ is great, but the time, extra steps required and file size have turned me off to iridient I haven't played much with Luminar.
3. The Fujifilm simulations are pretty magical. I use the sooc jpegs a lot. They do sometimes need a bit of massaging to get them where I want them but overall they have something special about them that i have never been able to replicate elsewhere. The LR fuji film simulations come close enough to use a starting point, but don't really measure up in my book; they offer a good starting point for deeper raw processing. Basically - if I nail it in camera -> fuji jpeg+a few minor edits works really really well.
Sorry for the long-winded reply. And congrats on the X-T2!
