I don't care if Quinn is like the MC, personally I like Quinn's character more than the MC's but I'll never pass up a chance to butt in and talk about muh queen
Now obviously a DIK MC is infinitely more alike Quinn than a CHICK MC, don't think that's debatable, so let's talk baseline because that's more interesting.
Baseline, we know the MC grew up poor as you said, alike Quinn, so they faced similar class challenges. They both love their father, although I guess you can treat him pretty badly imo in the game so let's just say what we know of the MC's history indicates he only had his father to depend on, like Quinn.
I would argue that the MC's baseline is not more empathetic than Quinn at all, let alone substantially, based on one event - the MC kicking the shit out of that kid in high school during the flashback we see. We know that Quinn is a nasty bully bitch drug dealing whore but she never does anything to anyone approaching that level of violence and aggression. We don't know if Quinn would even want to, I'm not saying she's harmless by any means but when she gets punched in the face in the rain she doesn't try to fight back at all, she becomes timid and defeated. This isn't necessarily an argument as to why Quinn and MC are alike but more stating that they're not as far apart as you make it seem as far as empathy goes.
I'd also debate that the MC follows the lead of others since you can pretty much call the shots with Derek from day 1 on either path, which almost everyone will do in order to wear the dildo at the right time to win Hell Week and not lose points with girls, plus he's effectively leading the DIKs to repair the mansion in the latest episodes. Whatever path you're on, in ep 7 Sage invites the MC to plan the Halloween party with her and Quinn, which shows that both him and Quinn both have leadership potential, a trait that I'd say makes them more alike than the MC and almost any other girl aside from Sage herself and arguably Bella. Don't think I'm alone in assuming that leadership is in the MC's and Quinn's futures at least.
The MC is undoubtedly more willing to accept help and criticism than Quinn, but this could change. The rain scene shows Quinn can accept help, though admittedly accepting criticism is one of Quinn's biggest character flaws which is not shared at all with the MC. Whatever path you're on, the MC is fairly introspective and self-critical at times and I appreciate that.
So on baseline, without looking at DIK or CHIK paths, I feel the MC and Quinn are more alike than the other girls, for what it's worth, or at the very least they're not massively dissimilar. Growing up in similarly shitty situations is something only the MC and Quinn share between the LIs, that we know of, and lived experience is a big thing to have in common. They're also both natural leaders by my estimation, although both Sage and Bella share this too so it's not that unique (also Lily if she counts as an LI, my penis says yes). Other than that, I'd say Quinn and the MC have simply grown differently in similar soil, but that similar soil can't be understated as far as character growth goes. As Quinn and the MC grow closer, I'm super interested to see what she'll think of his upbringing once she hears his story and whether it'll bring them closer together - I think Quinn will be far more likely to share the shit in her past with the MC than anyone else because of it.
tl;dr Quinn and MC both poor, both leaders, that's enough to have more chemistry imo than all the other gurls probs
Literally no one forgives Quinn's shitty actions, we just wanna bang her
I will point out tho that a DIK MC can be played incredibly similar to Quinn. A DIK MC can be quick to kick everyone's asses (violent, not very compassionate), can rat out Tommy to Heather and backstab Derek too I think (would never do my boi like that but I'm pretty sure you can), and Quinn can act mopey too during the rain scene.
Again I personally couldn't give a shit whether the MC and Quinn are alike at all, I don't see that as important to a relationship really, but the projection is running in both directions here to be fair. The one thing the MC and Quinn don't lack is chemistry, ASSUMING you are on her path, which is a prerequisite for this whole discussion really otherwise why does anyone care.