Hi,
The idea is fine. Implementation, not so much.
Some activities very much favor Cha-based classes, and for no good reason: Why not a Wisdom-based check instead of Cha(persuasion), to perceive who might be selling an item? Or an Int-based knowledge check, to know who is who in town? Int(investigation) makes more sense than Cha(persuasion). There's no tie-in to backgrounds that might be helpful either, or various divination spells that might provide Guidance of some kind. And if it's going to be a Charisma check, why does Persuasion work but Intimidation fail?
BTW, a level 20 character skilled in persuasion with Cha 20 who rolls a 20 after maxing out the +10 bonus has achieved a 41, barely enough to get onto Table I. This (bad design) might be intentional, but Bards and Rogues can get another +6, which utterly changes things.
Speaking of utterly changing things, maybe just label the tables "Casing the Joint: Preparation for a Magic Item Heist." Because once a seller has been identified, why pay crazy prices? Heck, you can build an entire campaign around this. Naturally, I see no mention of this because this consequence was probably not considered.
This is the kind of material that limits rp in the name of expanding it, sort of like video game NPCs with limited possibility for interaction.
On to carousing; I'll stop when I tire of typing. Cha makes more sense here, I suppose, but why not Deception to worm your way into people's good graces, or Performance to wow a crowd, or get a patron or groupie? Or even intimidation, to convince people that they'll be happy if you're happy? But of course, Int gets no love as usual: Why not investigation, to find people who are likely to have interests sympathetic to yours? BTW, the carousing outcomes are limited and, once again, limiting. Even silly. It's silly to think that a guild master will "help in any way possible" just because you partied with him, but if it does happen, it's silly to think that he'll help exactly once unless you party with him again.
Once more, NPC reaction and motivation is crunched down to fit into 8-bit container.
Just in case you thought things couldn't get worse, along comes crafting. Notice how crafting isn't really a downtime activity because it totally depends on obtaining the materials through adventure? (If crafting is a thing, then why doesn't anyone sell the item? Never mind.) Notice how it costs more to craft an item than to buy it? Right.
Oh, look: Crime. I suppose that's full circle, and I'll stop here. This section isn't really about crime in general, only thieving. Unless, of course, forgery isn't a crime, blackmail, armed robbery, kidnapping, arson... Even for thieving, this section is pretty pathetic: Why be satisfied with a mere 1000gp heist when you can start by finding a magic item to steal using the first section, or take advantage of all the contacts you made using section 2 (less obvious, since the value is not determined here but still)?
Not down with these downtime rules,
Ken