Well firstly my assault rifle build is rather different to yours. I started out with 6 strength, increasing to 7 to pick up full auto (although perhaps not too early, those extra two shots in an already ammo-expensive burst make things difficult...), plus 6 dex and 6 agility to get sprint at level 1 (hugely important, especially if you're using a high armor penalty build), and point shot later on (its damage is increase by smart modules as it counts as a special attack and you can use it every turn). all my other stats were the same apart from 3 Constitution and one less point in perception. Constitution isn't necessary for this build as you'll have options to avoid taking damage like high-quality armor (particularly tactical vests), and bear traps (the skill requirement to use them is super low and they will disable anyone for two turns). You need int 7 so you can pick up gun nut early, say at level 4 or 6, it's an indispensable ability if you're crafting your own guns.
The skills I chose for my assault rifle guy were
-hacking + lockpicking (It's the way I play every RPG. I like breaking into places and you'll certainly get your money's worth for these skills
-traps(You could probably leave this skill if all you're going to do is use beartraps but if you'd like to use mines and also disarm landmines for some small exp rewards (and so you don't get blown up) it's worthwhile throwing some points into this most levels.
- Mechanics, electronics, Tailoring (Increase all 3 to their max, but once you're starting to hit level 10 or so you can maybe skip a level and put the points you saved into some other skills to bring them to a useful level. Chemistry is worth taking to ~15 for armor crafting purposes, but that's an occasional thing. You could increase it more if you plan on crafting grenades/mines or special ammo
Feats to look out for are aimed shot, sprint, gun nut, suppressive fire, full auto, rapid fire+point shot, concentrated fire, and commando. Stuff like sharpshooter and critical power go well with any ranged build, and considering that you'll be putting out a large volume of fire expertise and recklessness would be good too.
as for your other questions:
-You don't need to put any points into evasion and dodge if you're using heavier armor, besides you can get some free points from a pair of tabi if you're using them.
-With 3 will psionics will not be worthwhile, don't waste feats or skill points on them when you've got other things you can be investing in.
-Depends, persuasion looks like it's a requirement to take certain quests and also to allow you to take some quests in the direction you'd like, whereas intimidate seems to be more useful to avoid fighting. I've often thought it may have been worth it to shave another point off my perception at character creation to give me 4 will, so I didn't have a penalty to my persuasion score (having 3 in a stat penalizes any relevant skills.)
-Mechanics, electronics, and tailoring are 3 extremely important crafting skills. Biology is more for people going to be crafting psionic equipment, or when combined with chemistry for people using crossbows. Try and end up with 15 chemistry at some point so you can craft using a particular kind of animal leather that's handy later on. Tailoring will be useful the whole game as you can attach overcoats to practically every set of armor and you can also make balaclavas and tabi. With high quality black cloth you can make a full set of stealth armor to keep in your inventory, and have some limited sneaking capabilities even without a single point in the stealth skill.
-The blueprints for gun ammo are rare and hard to find, some merchants stock them but it's extremely uncommon.
-Recklessness hurts low armor players more than high-armor ones. With strong armor crits aren't going to be that dangerous.
lastly even if you're concentrating on assault rifles, take a sniper rifle along with you as well. With some attachments combined with aimed shot you can one-shot a whole bunch of enemies which is very handy, for both opening combat and also for slowly taking out a bunch of strong enemies like sentry robots/turrets