If one is arriving past midnight from a domestic flight on AC at T1 and leaving on AC first thing in the morning ( 8 hours later) - best option, if it exists, is an airside hotel?

Does it exist? If not, one option is staying at an landside hotel - Sheraton or ALT, or some other hotel further out?

Can one forego a hotel and just sleep on the seat at the gate? Can one go from the domestic terminal building to the international terminal concourse at that time of the night (ie via the airside route)?

My question pre-supposes that the check bags would not need to be picked up at YYZ - as the second flight is considered to be a connecting flight?