my bike is old 26 it seems to be old EA3 bike , i have 26 x 1 3/8 wheels ( 37-590) , with old suntour freewheel
the rear wheel stuck 1 week ago , and i'm gonna change the bearings balls (steel balls ) for the both rear wheel sides , and i have some difficulty in replacing the inner side ( freewheel side ) bearings balls but i will resolve that by removing the free wheel
first question is : this is my freewheel pic



does this park tool fit my freewheel ?
New Lifu Bike Tool for Suntour 2 Notch Prong Freewheel | eBay

2nd question : what is the steel balls recommended size for both sides ? and if i need to change the freewheel steel balls will it be the same size for the wheel one ?

3rd (last) question : if i wanna buy a new derailleur for the bike , which kind fit?

i know that going to LBS is good idea but not for me , if i have enough money to do i will do without asking someone
i know also that my bike is too old , but that's what i got for now and i cant buy a new one .

thanks in advance