Impersonator chassis got me thinking about this, so I figured I'd see what it would look like. Ideally, not just looking like a person, but actually being able to speak on behalf of the Mechanic.
So, just taking the chassis gives us trained deception, looking like an ancestry, and +2 to the DC to see through an impersonation as that ancestry. However, they can't speak or hold anything, so it's not going to hold up for anything other than "not drawing attention in a crowd". We're giving up a lot of health and damage, as well as a bit of accuracy, for this, so let's see what it takes to get some actual value.
Fortunately, we start out with a free Commercial Customization, and Mechanic provides an Integrated Weapon Mount. Having a sniper rifle or something in the weapon mount probably solves our damage problems, buuut it gives the disguise away. Oh well, ten-minute install/uninstall time means it's not the end of the world. The Commercial Customization gives us Artificial Personality, critically giving us speech and the ability to attempt charisma-based checks.
They still can't use their hands, which is probably a good thing to remedy to draw less attention. So we'll need one feat for Commercial Customization to get Manual Dexterity. At this point, we're doing okay: we have a person-shaped bot who can casually interact with things and lie. This seems like a great spot to point out that under the current rules, companions can never activate items! This might need to be updated to "can't activate magic items" or something like that, since it does feel like a robot companion should be able to do tech item activations at some point.
A second Commercial Customization feat would help a lot, grabbing Skill Module for Diplomacy. A +1 Charisma is nothing to write home about, but this will let them smooth things over.
We'll also have feats locked in for Mature, Graceful/Nimble (hopefully graceful covers charisma, unlike nimble?), Specialized, and Elite to keep our companion up to date.
When we get to level 6, we need to take Tactical Customization for Expertise Module (Deception) because companion advancements were designed for animal companions, and therefore never advanced the starting skill.
So far, that's 1st, 2nd, 4th, 6th, and 8th spoken for, along with 14 and 18.
At 10th, we'll really want Advanced Customization for Sapient. That frees us up to retrain the Commercial Customization used for Artificial Personality, freeing up a second-rank slot, or that can be used for Upgrade Slot to get a Glamer Projector installed for easy outfit changes.
At 12th, as long as we don't feel we need +2 diplomacy, we're good.
At 14th, we get a specialization. It's not exactly thematic, but Bully gives us +3 to our charisma mod, and we'll take that.
At 16th, Superior Customization gets us Glow Up. It "increases" our charisma to +3, when we have +4. It feels a little bad investing so much into this and only getting that +1 advantage over a tank who took another specialization.
We don't know what level 18's Elite Drone does, but given how important the other similar feats are, I assume it's also important.
For the capstone, Ultimate Drone finally gives us a charisma boost. Diplomat gives us master diplomacy (freeing up Glow-Up and possible skill+expertise modules), and a whopping +4 charisma. 20th level is very late, but +10 charisma helps make up for only having expert deception with no item bonuses. That's... 10 for being a DC, 24 from expert, 10 from mod, and 2 from chassis specialty. That's a DC of 46 to recognize that they're a robot companion. An on-level high perception score sees through that 55% of the time.
At level 19, though, it's pretty rough, with a high perception seeing through it 80% of the time. At 13, before specialization, that's... 10 for DC, 17 from expert, 1 from mod, and 2 from chassis specialty. That's DC 30. An on-level high perception score sees through that 85% of the time.
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Overall, this feels like a lot of work and investment. It feels like we're missing pieces of the playtest, too. The animal companion specializations don't map super well to some of the options robots get, and we're missing the level 18 option. It feels like impersonator acting as face has to make a lot of tradeoffs while still requiring everything to be invested into the concept. Almost the only free feats were ones that were freed up by a customization covering something that used to be necessary.
Can a Mechanic's Drone maybe get a delayed customization progression, or feat that acts like a bulk deal? Even if it's something like Tactical Drone giving a Commercial Customization and Refined Chassis giving a Tactical Customization, where you get the previous rank of customization...
Impersonator Chassis feels like it should also allow any integrated weapon to be concealed while not in use unless somebody beats their Deception DC for impersonation.
*(When trying to build mechanics, I noticed the feats all seem pretty siloed. They did a good job making feats that work for 2 but not 3 of the subclasses, but for the most part you're picking one subclass and then picking nearly exclusively feats for that subclass that upgrade that subclass. This is why I love the level 2 "remote access" feat- it's so unique!)
The only mandatory Mechanic survey question addresses this and requires you to tell them whether you want extra final release feats that are exocortex specific, give general utility abilities, give new mods, or other.
The "or other" was the only place I saw to freely write any input, maybe people can try to sneak a few paragraphs of general commentary into that one.