Why the secrets? Toy hauler make and model is secret. SxS make and model is secret.
At least with the make and model of the TH, we could see what the manufacturer thinks the empty tongue weight is, which would help some with the advice.
The toy hauler manufacturer should also provide some guidance on cargo capacity for the toybox area, but again, since that's such a closely guarded secret, that's something else we're left guessing at.
Reality is probably closer to Grit Dog's comment, and the SxS just fits in the trailer with very little wiggle room. So it boils down to you haul it or you don't.
Load up and see what happens. It's going to be obvious sitting in the driveway that it's not going to work, and if not there, it will be obvious within a few miles of home. It's not going to feel "just fine" until you're 1000 miles from home, then suddenly become a problem.