I got some once fired brass from Midway

Wow thats cheap. Good find. As long as the case doesnt have any cracks, it should load fine.

 

Those are CCI primers, those just pop out while resizing. The ones that are crimped I think they make a tool that uncrimps the primer pocket.

 

CCI Primers

I don't know if any new ammo is loaded with CCIs, Thats all I use when I can get them, Lee's old reloading manual warned against another brand and I took that as good advice.

I have never rec'd anything from Midway that wasn't A#1, so I am guessing that your 9mm brass will be good.

 

Silver cases or silver primers?? Yes the nickle plated cases are reloadable. Ive never bought once fired brass but, I know when I buy reloaded rounds they will sometimes have cci primers loaded.

 

are the cases mixed or all the name brand?

 

Most new brass cased ammo is primed with brass colored primers. Just because it has nickel primers does not necessarily mean it was previouosly reloaded. I would check the brass against others with the same headstamp. If all of the "brand X" brass has nickel primers I would be less suspicious.
Beware of Glock fired brass. It will be more swollen at the base and you cannot properly resize with conventional tools. To correct the Glock fired brass you will need a Case Pro or Magma Casemaster.
If you don't know how to tell the difference, drop me a PM.