With thought control as a support discipline it's much harder to make a proper hybrid, especially with a gun oriented character. Thought control relies heavily on your skill vs enemy resolve so it's naturally pretty much an "all or nothing" school which makes it ineffective for everybody without high WIL score. Hybrid characters who want to use it reliably will most likely be glass cannons which is dangerous because of -25% max hp from PSI but it's still doable with Locus of Control and strong crafting (mainly regenerative vest and high capacity shields). Sniper rifles are not very stat hungry weapons so they present an interesting option, especially because of the synergy with the thought control ability neurovisual disruption:
http://www.underrail.com/wiki/index.php?title=Neurovisual_DisruptionBeing able to restealth in mid-combat without flashbangs (which you should use as well) is godsend for a sniper.
This is what I had in mind (think of Ezra from SGS):
Last three feat slots are flexible. You could put something else more to your liking.
As a sniper you could infact even dump STR entirely and strictly use the unique Dragunov sniper which has no STR requirement at all:
http://www.underrail.com/wiki/index.php?title=DragunovUnfortunatelly it has no smart module either so your snipe damage will not be all that good, possibly not enough to one-shot tougher enemies.
You could save 2 stat points from that but I would still recommend to keep 5 STR for 2 crafted Spearhead snipers, both with smart module and rapid reloader so you can shoot for 24 AP. One is with regular scope specialised for snipe attack which will help you with precision, the other with anatomically-aware scope for your Aimed Shot criticals and all shots where you don't need the extra precision from the first sniper. Ideally you will open up with Snipe, use Aimed Shot, then some PSI in the next round and restealth if possible. If not, continue using PSI until you can use Aimed Shot again. Basically you're balancing sniper special attacks with your PSI cooldowns and your PSI point pool. That's why you don't really need a PSI beetle carapace on your tactical vest. It's much better to keep your regenerative vest with 0 armor penalty thanks to reinforced fabric and Nimble. It will keep you and your shield longer alive and compensate alot for low hitpoints. Doctor's pouch is naturally the most usefull belt for this build but I'd advise you to use +30 HP lifting belt until you can craft a proper shield. Early game it translates to something like +50% hitpoints on a hard difficulty glass cannon.
6 AGI is a no-brainer, you need it for some basic defense, stealth and Sprint is always helpful to kite away and reposition after you've done your shots. 7 INT is very important for this build, not only for the crafting feats, but also because this character will be extremly skill hungry: Maxed thought control + some psychokinesis (mainly to qualify for force field and eventually electrokinetic imprint), maxed guns, maxed stealth, maxed dodge + evasion, solid mechanics, electronics, tailoring + some biology for the regenrative vest and hopefully a bit of hacking and lockpicking. The last two are optional, I would not raise them beyond 70 effective skill (incl synergy bonus, Huxkey, Jackknife and DEX Eel), should be enough for most basic locks. It will be quite a challenge to balance all those skills, especially crafting, even with regular use of Junkyard Surprise (temporary +2 INT). One could dump evasion but the shield will then get eaten up pretty quickly, even with huge capacity crafted via Power Management. Stronger melee attacks can get alot of damage through the shield so dumping dodge isn't the best idea either for a non-metal armor glass cannon.
Skillwise you'll probably have to make some compromises along the way. After the few first levels, at level-ups best raise crafting only so far until you can craft your desired item WITH the use of Junkyard Surprise (9 INT total). Always use the character creator to exactly see how much basic skill investment you need (use +2 INT option).
http://underrail.info.tm/?build=AwGlEYBYQJgVhAgzCAbCF4IxAdhOEgqCQUWQocgBwiSmjXTWlLPRV3Fg-BABut hey, this is all just advice... do whatever &%$& you wanna do!
LOL just kidding. This is all theorycrafting for I never actually played a PSI oriented sniper. As a permadeath player I'm usually too scared of playing PSI glass cannons but if you give it a go tell me how it works out for you.