To answer your questions. #1 As long as there are threads from your wheel stud protruding out of the lug nut holding the spacer on, you should be fine. Again, maybe a good time to remove all spacers and follow the directions above. Not bad practice to work that into your maintenence on a yearly basis. It could be that every time you apply torque to the nuts holding the spacers on you are breaking down the chemical bond of the loctite if you are using any.
#2 Any wheel studs should work as well. There are minimum standards of strength that they have to be manufactured to in order to be sold in the first place. No one is going to be selling grade 5 studs to anyone, and I'm positive that when guys are installing their bolt on wheel hubs in their Tacomas that they are changing out their wheel studs with the ones they come installed with from Autozone, Napa or otherwise.
#2 Any wheel studs should work as well. There are minimum standards of strength that they have to be manufactured to in order to be sold in the first place. No one is going to be selling grade 5 studs to anyone, and I'm positive that when guys are installing their bolt on wheel hubs in their Tacomas that they are changing out their wheel studs with the ones they come installed with from Autozone, Napa or otherwise.