To answer your questions:
Yes, it's DOMINATING-viable
Yes, Mercantile is excellent for crafting builds. The threshold you want to hit is 105, but keep in mind you'll have +2 Int drugs available and a +3 to all skills food, so factor that in accordingly. Once you touch the threshold, it's perfectly fine not to have your skill be that high when you interact with the merchant every following time. You just need to unlock the merchandise tier and it stays unlocked.
Sprint is of almost no use whatsoever to a psi build, and Conditioning sounds good but because it applies after all your other DR/DT (and not alongside it) it's not really all that big a deal. It's not worthless, mind, it's just underwhelming.
Yes, dump Agi, drop Sprint, and take Int to 9 so you can craft better
Nope, you shouldn't miss any lore at all in Expedition with that build. You will however miss a lot of possible avenues to solutions - but you'll be able to take advantage of others. Expedition has truly wonderful permissivity for various character builds, so no matter what your build (OK, *almost* no matter what) you'll miss out on a lot of possibilities but be able to make use of many others.
EDIT: Oh, and some unsolicited , min/maxing advice that you should feel free to ignore- take all those points out of Throwing, put a few in Mercantile so you can get that 105, put most of the rest in Persuasion until your effective skill is 87, put 25 in Intimidation, and use the remaining 20 to cap psychokinesis and Metathermics. You can also safely pull Thought Control down to 75 if you want to free up more points, but you may not need to because your Chemistry is way too high - pull it down to 45 or lower. All you need is to be able to make Mk IV grenades. The jump to Mk V will be so late in the game that your psi powers will have come into full form and you won't even remember to use grenades because you'll be too busy destroying the world with your magical cave wizard powers.
If you do pull TC down to 75, you could pick up enough Hacking to get 130 effective and *still* have 25 points left over.