1991 Mazda 929 Various things with my just purchased car

I'd like to start by thanking you guys for my last question it was worth the donation and u were right on target. Now that I have to replace the head due to all bent valves on my other car I got this for a steal and want it to run sound before I take it to the road. So here's the issues I found.
When it starts its having a little trouble turning over, it does eventually or it won't once in a while. It's cranking but just barely not enough. It has a brand new battery and I tested the volts while running and the alternator seems fine as well. All I can think of next is the starter after that but help would be nice. After it does turn over if I rev it, theres a loud noise and it only happens that first time. The fan comes on high n loud and it idles high. Around 2k rpm til it idles down some then rest a little about 12 to 1400 rpm. It only idles high in park every other gear it idles normal.
This Mazda has a hold light which is blinking and speedometer doesnt work, which ive found has something to do with the electrical in the transmission. Im taking it to a dealer for that but I dont want them trying to hose me for a bunch of other things. There's no leaks and the fluids look good and it doesnt overheat. Im gonna change the plugs, it has new wires and eventually, if I think it will be a good car, get a new timing belt just to be safe. Narrowing down the possibilities would be great help. Thanx