2000 Caravan 2.4 liter questions

Just a few questions about my van that I just bought -


What is the most common presentation of a blown head gasket on the 2.4 liter engine? I've checked all the visual aids and a few of the mechanical aids that show a blown head gasket, like oil/water mixing and water in the exhaust, and I show nothing, but a mechanic told the guy I bought it from that it was a blown head gasket, and it's been over heating.
Is there a common problem with the 2.4 liter engine over heating?
Was there a 2.4 Caravan model from 1996-2000 that came with a tach?
If not, will the tach from a V6 model work?
What other things should I check before putting the van on the road for daily driver service? (It's in the shop right now, I want to make sure I get everything checked out before I put it on the road, since it was already inspected a few months ago and passed.)
Why does the blower randomly stop working, and why isn't there heat in the HVAC system? (I assume this one is related to the problem with overheating, possibly a plugged/stuck closed thermostat or a plugged heater core, we're looking into it.)That's about all for now, I'm sure there will be other questions in the future though.

Thanks in advance for help!

1-4?
5. The timing belt should be changed every 120K miles according to the Gates.com website. If the TB breaks you're stuck wherever you are at the time. The good news is according to Gates you have a non-interference engine meaning it won't eat itself if the TB breaks.
6. Your intermittent blower may be the blower relay. I had the same problem a while back.

So far, the water pump has failed, and there is still no indication of a blown head gasket... I bought a new water pump, but didn't have time to put it on, and the crank pulley broke while I was pulling it off, so I need to get a new one.