First time poster - I searched but haven’t found anything quite on point. Thanks in advance!

We are interested in buying a home that’s been gutted by the seller and left in a condition that is not habitable, aka we can’t get a traditional mortgage for the house. The lot is amazing though and the shell of the old home has tons of potential. Our only option for what we’d like is to do a construction to permanent loan (jumbo, 20% down), but I know we need detailed plans/costs/signed contract to apply. My question is about timing — we haven’t made an offer yet on the property, but we’ve been interviewing architects and builders. The timing feels like a chicken or the egg situation - we don’t want to spend the $$ to get detailed schematics if we don’t have an accepted offer on the property, but we can’t even apply for the loan (and thus know if we can even get this property) until we have detailed schematics. It feels super tight to make an offer, draw up plans within like, 2-4 weeks, apply for the loan, and get everything appraised and approved within a standard 60 day closing. Is our only option to ask for a long closing when we put in an offer? Has anyone ever done this? Was the timeline doable? Any suggestions or comments? Thanks!