So there is no tense confusion? I wasn't sure because normally 'will' puts it in the future tense and 'had' in the past tense. In German though, 'if we had' is the future in the past e.g. They asked me if I had a car but I said no because I didn't want to give them a ride ( I still have that car).
Yes. With no other context, I'm assuming that this is more or less the same day, the immediate future.There might be the possibility, however, of other visitors moving out in the near future - which would mean that, even though your house is full at the moment, you "will have enough room" for your friend to come and stay with you next week.
Well it was a made up sentence.Ah, but telling them you did not have a car because you didn't want to give them a ride, is hardly polite. The tense has no impact at all in the politeness; the intent does however.