so I have a few questions :
Let's see....
"-how can I unlock the locations ? there's the college, the night club and the church I've never gained access to (assuming the saturday date count as access to clothing store and cinema, if not, I've never accessed those two place by clicking on it outside of the house)
I already met the customer that tell Natasha about the night club but wasn't able to gain access of it"
No clue about College and Church tbh.
Cinema and Clothes shop are only "available" through an event (So I have no clue why they are included in those locations) when any other family member but the mom takes her (the mom) out on a Date on Saturdays before the evening. So far the only really useful one is to buy her the "slutty outfit" when being the Hubby or the Son. There are little scenes for other stuff but not much to write home about.
The Car Dealer is available for the Hubby every weekday until afternoon.
The Cafe Shop is available for the Daughter every weekday until afternoon.
The CLUB you asked about is only available on Saturday Evenings for everyone (But careful, a "Date" with the mom takes the entire day, so no Club afterwards).
This means imo, that College and Church don't have content yet (College probably being for the Son).
"-what are the utility of perks ? (something explaining what each perks does and what we can gain from it could be usefull in the game, for exemple, I got the perks perverted and I have no idea what it does)"
I agree, some sort of Documentation or even Tooltip would be REALLY helpful. Now some are pretty much self explanatory anyway... Family Lover (Incest possible), Gay, Nudist, Foot Fetishist and so on. Coomer seems to increase the possible lust gain from interactions, enables at least two extra actions for the Dad and also gives a small automatic lust increase every day. Not sure what "Pervert" and "Nymphomaniac" do yet, I would guess they would allow some extra actions (maybe not in the game yet).
"-is there a way to lose perks when you've reached the max because you want to try and gain another one ?"
None that I have found so far. Maybe in the Hell shop, but that doesn't work for me at all in this version, I only ever got offered the Dancing all Night one.
-for Natasha or Isaak to masturbate with the door open (and thus try and give the family lover perks to the one who spot them), do they need both coomer and nudist or is coomer enough ?
I don't think that there are prerequisites, at least not Quirk wise (maybe a certain amount of lust though). It's simply a certain probability to get the scenes when you enter their rooms and then another probability check to actually get the quirk (so a lot of scrolling back and forth).
Hope this helps a bit.