Well you picked a doozie for your first one. probably more relays and steppers than any other EM game.
tackle issues one at a time, and don't get caught up in thinking one issue is related to the next, they often aren't.
So let's start with the 1000 points and your stuck/buzzing score reels and relays.
Yes, clean and adjust the 1000 point reel. But also put the game on player 2 and see if it's still happening. If it isn't, it's probably the 1000 point reel. If it is, check the often overlooked 1000 point relay in the back of the head. In fact, clean/adjust (if needed) all of the point relays in the back of the head. These are often a source of trouble and people don't even realize it.
On my Grand Prix, the game wouldn't score AT ALL. No points. I checked all sorts of the usual suspects (index relay/game over etc.) before realize every single one of the scoring relays in the head needed attention. That's where I'd check first. Good news is these are very easy to locate and service.
You also may have a stuck 100 point switch somewhere on the playfield which could explain the weird spinner and eject issues. But again, could also be those point relays.
Good luck buddy! You are gonna need it!