1. Is going lower Thought Control an option - it is more of a general cc skill here than anything else? Does lower Thought Control reduce the chance of landing skills like Rage and Fear? I can't quite remember - it's been a while.
2. Reducing Psychokinesis/Throwing is an option.
3. How much Chemistry/Mechanics you need for MKIII? Gosh, I really have forgotten quite a bit.
4. How much Mechanics/Electronics/Tailoring do you think will be needed in the end?
5. Having more Mercantile is always welcomed. Using Under Pie to unlock the higher stores is a very good trick. How much Mercantile would you need for that in the end, and how early, in your opinion should the build invest in it?
6. What do you mean by TM? I assume it's Time Manipulation
1) Not really. You play on DOMINATING, right? You're going to need to break enemy resolve, and I usually recommend an effective TC of 200 or so for that. If you were playing 16 Will and multi-school psi, you could get there with 75 points in TC, but I think you need all of them to make sure you clear resolve. If you plan to use it regularly, don't give the enemies any more chance to resist your TC abilities than you have to.
2)Yeah. Three Pointer isn't reliable even with a dedicated throwing build, so I don't like it much. Personal bias aside, it can be tough to recommend it - it's only good with high Throwing, but it's not good enough to be the only reason you go deep into Throwing. If all you want is to reliably place grenades, you can do that with 50-60 effective skill.
3)When in doubt, go to the wiki:
https://www.underrail.com/wiki/index.php?title=Blueprint:_Hand_Grenade4&5) See above (edit: if you want to go in 20 points really early for the SGS benefits, that makes sense - but if not, then don't bother going into Mercantile until you've cleared the Depot, unless you really want TiChrome before you go in, in which case you need a few dozen points to unlock Blaine's inventory so you get an RNG chance for him to have a bar in stock)
6) Yep, you're right. Temporal Manipulation. Getting that early will be a huge help for you. The basic ability will get you safely through the Retake The Outposts quest; the LTI and psi slow will just be very useful in general, and once you've cleared the Depot you'll get some really, really nice abilities. So try to pick up some TM early if you can - no point in getting any more crafting than you need, until you need it.