Jeffers: Echoing pretty much the consensus here, he's probably the catcher to trade. His defense has never been stellar and the cost to keep a player entering his decline is too steep compared to other uses for that money.
Larnach: He's a paradox and a dilemma. The Twins currently have no fewer than 10 outfielders on their 40-man roster (the Twins 40-man page somehow has Keaschall and Kreidler swapped) and yet somehow we seem short and Larnach feels indispensable all of a sudden. Is Alan Roden really a replacement for Larnach? The Twins remain with a question mark about him instead of answers, a year after acquiring him. Here's the tie-breaker for me: Larnach's numbers at the plate are better this year, but his batting average on balls in play is at a career high (especially against RHP), so if he comes back to earth on that axis then he's basically the same batter we've seen the past several years. And his defense, while usually unimportant, remains a small negative. I would trade him at the deadline, grit my teeth, and hope Roden will develop that final step into being a full-time starter, which the team's scouts must have said was possible given that they accepted him in trade. I don't have huge expectations from Roden but his slightly better defense probably balances slightly lower offense, and he's under cheap team control for longer. It depends as always on the return in trade, as I have no interest in getting a 25-year old glove-first SS currently at AA.
Bell: I don't know if we'd get much in return for him. He's on a good run and that could evaporate but I'm inclined to hang on to him.
Go for it or build for 2027? 2023 is my evidence that even a modestly talented squad can do the franchise a lot of good - that series against Toronto was tons of fun and should not be downplayed. I think it's possible to do both (go for it without mortgaging the future) but a good deal of wheeling and dealing at the deadline will be involved. You can;'t trade Larnach or Jeffers to a contending team and expect MLB-ready pieces in return for our own contention efforts, so they need to be traded for excellent prospects, and then attention be turned to bottom-feeder teams who would like prospects in return for their few useful pieces. I've probably played too much OOTP and it colors my perception, but prospects are the essence of "fungible assets" and should be used to smooth out the process of acquiring your eventual pool of major league talent. E.g. Roden should probably have been traded last off-season as part of a package for acquiring solid bullpen help, for example, once the Twins committed to Larnach another season. It's this big-picture issue of either committing to talent or else moving them in trade that is one of my biggest gripes with this FO - they acquired a guy like Roden and then let him die on the vine (injury this season being an extenuating factor).