I’m just trying to connect some seemingly separate issues. It would be weird for your starter, water pump, and some kind of ignition component to all have separate problems/failures all at the same time. Like winning the lotto kind of weird for odds.
But a starter failing like you described can be caused by the flywheel not spinning, which is caused by a seized engine, which could be caused by a failed water pump and an overheating engine. And that’s not weird for odds, that’s a logical sequence of events. But I’m not there and I didn’t see what happened, I’m just going on the description.
The crank bolt should be 1-1/4”. If you don’t have anything that large you can pull the spark plugs and see if you can turn the engine with the fan belt or pulley. With the plugs out the engine should actually spin pretty easy.
As for the not seized thing, overheated engines don’t necessarily seize up when they’re still hot. They totally can, that’s usually a melted bearing thing. But they can also get ring stuck after they’re shut down. An overheated engine that would spin but not run when boiling hot could still seize up after its shut down, all the tolerances change as it cools and sometimes the rings will stick.
And the sender is just in the water leaving the block. But if the water isn’t pumping it’s not leaving, and the water around the cylinders and in the heads will heat up A LOT faster than the water sitting at the sender in the intake.
I’m just speculating, and trying to connect a bunch of issues with different components based on your description. I have seen overheated engines run “ok” and then ring seize after they’re shut down. And I’ve seen localized overheating issues from failed pumps.
I’m just stringing together the events in your description in a logical progression. I could be totally wrong (and hopefully I am!) about the particulars, but usually a bunch of different stuff doesn’t all fail at the same time unless there’s some kind of connection.