Thoughts ...
A simple voltage check won't determine whether the battery can develop enough current to turn over the engine. A load test is the only useful test.
A jump pack of unknown charge will give unknown results, at best.
You were asked to trickle charge for 24 hours, but did it for 10 instead. That is not enough for a 2 amp charger (24 hours may not be enough).
Richard provided a simple and effective test of the battery, but that wasn't done.
Tapping the starter with a hammer may move the rotor enough that the brushes or solenoid are no longer on a bad spot, but for how long; when will it need to be tapped again? The best that can be hoped for with this is to confirm that something is wrong, but what - lose wire, solenoid, brush?
I've not seen any real diagnostics performed. You can throw parts (and money) at it and maybe get lucky. Look at the number of suggestions and potential corrections - which is correct - where does one start?
Sometimes, paying the one hour diagnostics fee at a (reputable) dealer is the least expensive and most expedient way to get to a resolution. As for not being able to get it towed because it's stuck in park, the drive shaft can be removed and it can then be pushed.
As for parts, IMO, go OEM for critical parts that are difficult or expensive to replace because you want to do this only once. As an example, your OEM starter lasted 15 years. The low cost parts alternatives are low cost due to low price labor and rebuild parts that reduce the reliability (this is how they offer lifetime warranties). If you save $80 on the part, but have to pay labor twice or have many down days, that's no bargain.
