FWIW, I've heard many things from the "front desk manager" that just isn't accurate. Like everyone else here, I take what any SVN employee says with extreme skepticism (and hope they're right, since typically they report a positive spin on reality). Asking for special treatment, like the OPs request, is just asking for disappointment, but still worth trying if it's important to you.
As for my own experience, Harborside offered to put a 1-bed Dlx unit on hold for my party so it could be connected to a 2-bed (non-LO; which = their 3Bd unit), with different check-in days. I didn't push for it (since I preferred those staying in the 1-bed to be far, far away from me...lol) so it got lost in the reservation process. And yes, this happened while I was on-site at Harborside (during an earlier trip) and the front desk told me it was possible. SVN would certainly have disputed the possibility on the phone. This type of reservation is possible, but I don't think there's any procedure for making it. Keep in mind that you can have any checkin or checkout day (but not both) using SOs, and paying nightly guests have no restrictions whatsoever. The resorts will always have certain units that simply don't match up to the typical check-in/out days.