Dan,
After you take the door panel off, the issue will probably be more clear. You still might find that the window regulator (aka track/slider) is the culprit. The regulator is riveted inside the metal door skin. The power window motor is bolted to the regulator.
If the regulator is not clearly a problem, the window motor bushings might be the culprit. The power window motor bushings, which act as the "transmission"/bufffer between the window motor and the regulator, are inside the window motor. These get reduced to useless nylon shavings over time. The window motor can be unbolted from the regulator without removing the regulator, but you will need to drill a small access hole to get a socket on one of the three bolts. Or you can remove the window motor by drilling out all the rivets and sliding out the entire regulator assembly.
Power window bushings can be found in the "Help" section of auto parts stores. "Help" makes generic replacements for a number of items. The three small nylon capsules, which are the bushings, will probably not fit your window motor without filing or grinding or sanding them down a little. This is not that difficult. The bushings cost about 7 dollars for a set. You can also replace the entire window motor if necessary, which I think cost about 35 dollars.
I am not sure about the best and cheapest replacement for the speakers, but the speakers are not a real common size (something like 6x8?). Maybe start with Internet search.
Note: There is very helpful information about removal of the power window motor, especially where to drill the access hole for separate removal, in this Forum (use the "Search" function) and on YouTube. You should also be able to find more information in these sites about replacing the window regulator, and about replacing the window bushings.
Let us know how it goes. And good luck with your projects.