I could see them go with Stroman, Sanchez, Borucki, Gaviglio, Panone/SRF as the basis of the rotation, although would certainly love to add 1-2 vets there as that rotation could look mighty ugly if/when injury hits Stroman/Sanchez. From the recent coverage, my guess is Estrada is gone for good, but it wouldn't shock me to see then try to bring Happ back if he doesn't get great offers from elsewhere.
In terms of a rebuilding rotation, the only flaw with the above is whether that's stretching guys beyond their limits. Ideally, those back-end guys probably all need a little more time in AAA, or at least need to have the option to shuffle them down to AAA for a month or two if things go sideways.
Jansen I don't think should go down to AAA, which means he'll need ABs at the bigs, although we probably don't need to force him into a starter's role quite yet. If he can get around 100 games behind the plate, I think that would be a solid goal for next year. What that means in terms of keeping Martin around as the backup to play 60-70 games only, or you eat his money and move him and go with Jansen-Maile with McGuire getting the bulk of the playing time in AAA , either option is good for me. Kind of depends whether Martin would rather play out his last year as a backup, or whether someone else is willing to give him more ABs. He's a sunk cost in terms of money, so if we ate literally the entirety of his deal, he could actually bring back a prospect with some value.
Tulo is a bit tougher to handle. He has no value at all right now, but until Bichette is ready, I don't think there's anyone who I'm desperate to give SS ABs to. Of course, even if he came out and had a great first half, you're still going to have to eat his entire contract to get anything back for, so I might be fine with simply cutting him loose. Another option would be using his money to facilitate another deal. Not sure which team might need a platoon SS and who has a ton of dead money on someone else's deal, but if we could get back someone younger and who maybe has a chance to better rebuild value, I'd definitely be up for that.