So, a potential idea that occurred to me recently while thinking about Plus One/Pathfinder/other utility abilities. Apologies for the rather long post!
Things We Know Already
(I) Crawlers can freely leave and enter parties.
(II) XP "leeching" is heavily (although not totally) based on being in a party.
(III) There are classes with utility abilities like healing/reconnaissance/traps/etc., which are useful, but do not have the raw power progression of combat/magic/shenanigans classes.
(IV) There are Crawlers in the dungeon who are going to be less combat inclined, or less certain that they can make it to the lower floors on sheer grit and willpower. Yes, even on Floor Three - look at the Astronomy Club! We're still only barely out of the tutorial.
The "Utility Mercenary"
Based on these, it seems that there should logically be a niche for a kind of "Utility Mercenary", who will join your party before the exit so you arrive on the next floor together, then immediately leave the party and tag along with you, renting out their class abilities to you without taking much XP. These often depend on Skill Levels, not XP or items, so they can even improve at their specialism over floors without draining resources.
Both sides benefit from this arrangement, as the party gains access to those abilities without the opportunity cost of a lower power-scaling class, and the "mercenary" Crawler gains protection, some payment in gold, and gain just enough XP by bystanding at [arbitrary distance] not to be insta-killed by mobs on whatever floor they're on. This is not necessarily a mercenary or selfish arrangement; it is ultimately a form of cooperation, where everyone benefits, and everyone's chances of survival increase, including humanity itself.
"From each according to their abilities, to each according to their needs."
So I think that if we're visiting towns, or the Vanquisher/Desperado clubs, we should be on the look out to see if there are any Crawlers offering these kinds of services, or who look lost and might be convinced. Also, if we manage to get in contact with the Astronomy Club again, we should see if they have anyone willing to sign on with us for this sort of arrangement*.
Plus One in particular is almost
designed for this, because you could wait outside the Vanquisher/Desperado Clubs offering your services, then join someone's party, take them inside for a fat fee, let them do their shopping/training, then escort them out and leave their party. This is both a point significantly in favour of Bounty Hunter the Dog, as it could potentially be rather lucrative just by trading other Crawlers for access to Plus One*, but also means that it is possible that we will gain access to it anyway at a premium.
Questions
Since we've seen only a fraction of the available class abilities, this also makes me wonder how much of a "grey market" exists in Crawlers charging or bartering for access to recipes, class abilities, and suchlike. Crucially, how much do the showrunners and the AI respond by trying to encourage, regulate, or disincentives this kind of cooperation? How do socials play into it?
Honestly, this seems like something Levi would know a lot about, so
@eaglejarl , what can he tell us? (Apologies if I'm very dense and it has been answered already.)
More generally on the topic of cooperation, if we gain useful map information/trap information/recipes, I think we should try to share them as much as possible. Both because morally it is the right thing to do, but also because it showcases the human spirit. The AI and showrunners may like that - the recaps have already emphasised images of humans helping one another in adversity, so it's clearly a plot element they're willing to focus on.
*(The best option for the Astronomy Club going forward, honestly, might be to sort of rent out their services as a "utility guild" in this way, where some members sign on with other parties each floor, whilst the rest of the Club fort up somewhere safe, possibly directly in a Safe Room if possible, until one of their members who is on a contract can give them info on an exit with a cleared path to it. Agreeing to help escort the Club to the exit could be a condition of contracting their services, actually. This depends on smart choice of classes rather than beelining for combat options, though, so we'll see if they were intelligent enough to work this out on their own.)
*(This is also true for Sysop + Wheeler Dealer, which I think we were already counting on to some extent. Although straight up starting a bidding war amongst Crawlers for our ability to roll boxes and transfer them seems like it might draw the ire of the showrunners and/or AI...)