I'd start by making sure all the vacuum lines are connected and in good shape along with the intake air tubing between the MAF sensor and the throttle body. Was any work done on the car under the hood recently? If so, you might start in that area, looking at vacuum lines and electrical connectors.
If everything looks fine, then you might start by replacing the DPFE. They are known to fail and could contribute to your P1401, O2 sensor codes. If the EGR system is know functioning properly, it might also cause the bank 2 misfires, or they may be an independent issue. I'd start with the EGR system though.
-Rod