There should be no issues with the printer connecting to the powerline adaptor, the only issue may come down to the frequency or network being incompatible.
Unfortunately you don't give the power adaptor model or the printer model so I can't be specfic but it should work fine.
Make sure you can connect to the powerline adaptor's wifi, make sure the password is correct and that the adaptor is compatible with the specification either being G N AC etc...
If the printer can connect and can see the wireless network pumped out by the power line adaptor it'll be fine to print over.
I have connected my wifi printer to access my Devolo wireless adaptor and works as expected. I share the printer and it's available throughout my network. If you set the printer to use DHCP it will be even easier for it to pick up the correct network settings.
RJ45 won't be an issue either. The powerline will act just like a long cable...
Hope that helps.
Edson