I need new bearings, a freewheel remover, and a cone wrench, I'm not sure what size on the cone wrench I guess 15 mm
For rear wheels, 1/4 is indeed the most common size. As for cone wrench, I have no idea. I keep 13, 14 and 15 close and haven't payed any attention to which of these gets the most use. And while it does make the job easier, you don't have to remove the f/w to service the bearings.
1/4 cone 15mm rear 13 mm front or 16 and 14 you can get one wrench that does all 4 sizes yes true 13 14 15 16 one wrench to rule them all but then you need a pair ha grow one wle
You may need a lot more than the bearings. If the wheel is really bad the cones may be shot with a possibility that the bearing cups are finished as well. If that is the case, your wheel is done, finished, toast. The only way to find out is to take everything apart. Don't buy anything until you have taken the axle out, the freewheel off and have inspected everything