The prae- prefix connotes a bit more than “before” in a purely temporal sense. Praebibere would be to drink in anticipation of something, or to drink as a salutation or herald of something. So it could mean “toast”, provided what you toasting is an imminent event.
The Romans, of course, didn’t toast important events by drinking; they poured a drink on the ground (a “libation”) as an offering to honour, thank or intercede with a god or the gods generally. In the context of something like a housewarming, the Romans would definitely have performed a libation.