Just wanted to say about the job/payment thing, if you have no intention of romancing and/or paying for Robin, just never visit their room (after a few weeks) - at least in the previous version Robin doesn't get shipped out until you find out that they're missing by visiting Robin's room in the orphanage (that is, Robin will still show up at school, etc. well after they ought to have been sold by Bailey).
That makes a 2k/week upper limit, and if you're willing to save-scum you could potentially "unlock" the 2k smuggling heist from Bartending a single shift. Pretty sure the heist is a once a week thing, but once you've got it locked in you can essentially ignore working entirely. From what I can tell it's not exactly required for Purity purposes, but if you're aiming for "zero sexual encounters" from working while making payments, I think that's the best option? Could be wrong, of course.
I kinda forget what the upper Skulduggery requirements are for the heist, but I'm pretty sure you can manage for quite some time on C+.