1. "Adjust Trait Chips" is one of the options if you click on an NPC plumbot. You actually don't need Advanced Tech to do this, but the success of removing chips is determined by your Bot Making skill. Even then, "stealing" trait chips from an NPC plumbot is considered very rude (but can be rather funny if you run across an obnoxious one), and will severely hurt your relationship with that Bot... though I don't think there any other ramifications.
2. Upgrading the Food Synthesizer does indeed require Adv. Tech skill levels. There are several upgrades, each requiring a higher Adv. Tech skill level. Note that the Food Synthesizers in the "base camp" (the house-like thing where you first teleport in) are already fully upgraded. If you're trying to fulfill the Life Time Wish to upgrade a food synthesizer, you'll need to buy a new one.
3. Sprites can be kind of cool at first, but get kind of annoying to maintain; HOWEVER, they are the single greatest way to increase the Adv. Tech skill. Have two sims each with their own sprite in their inventory. When they interact, you should have an option "Holo-disc...". (sometimes this option does not appear. I have no idea why, but if you go do something else, then come back, it's normally available so long as both sims have a sprite.) Click on that, then "Sprite chat" or something like that. This interaction increases your Adv. Tech skill ENORMOUSLY. I had one sim level from Adv. Tech level 8 to level 10 with only six times "talking" to another sprite. I have to believe this is a glitch, but it works consistently. If you don't have another sim that you control, find a local sim with whom you have a very good relationship (there is a relationship check, and sometimes sims will turn your Sprite Chat down).
