How much money has the Fed printed?
The Fed’s liabilities (technically broader than the true monetary base but arguably more relevant depending on your definition of “money printing”) are released weekly in their H.4.1 release. They appear in Table 4. Right now they are about 6.3 trillion dollars, up almost 2.4 trillion from a year ago.

They’re “validated” in the sense that the Fed has internal controls, external third-party auditors, and is subject to regular Congressional oversight. 

Yes, you can find a time series from the St. Louis Fed’s FRED service.