A wedding, huh? I just did one, and I think you may find this (very long) post helpful.
https://www.pentaxforums.com/forums/general-photography-industry/233422-my-fi...31-images.html
In addition to that, I would stick with the 55-300 for portraits, zooming in around the 150mm mark, and getting close to your subject. What this will do is despite the fact that you don't have a fast lens (i.e. a lens with aperture of f/2.0 or faster), it will be harder to isolate your subjects from the background. But it isn't impossible. You just have to be a bit more deliberate with your subjects as well as being very mindful of your backgrounds (are they cluttered? lots of people? poles? bikes/buildings/etc) It would help if you have a lot of space between your subjects and the background as this will allow you to take advantage of the compression effect of your tele lens and then separate it from the background. Done right and with the right environmental conditions (namely a clean background and lots of space), you won't be able to tell that from a $3000 set up for a straight portrait. It's just much, much harder. I would *highly* recommend practicing this with a friend/spouse/child/pet/abiotic object. It will help even more if you can recon the area before you go and do practice shots there.
Polarizers won't be much help to you unless it's SUPER sunny. Otherwise it's more trouble than its worth honestly. Especially if you aren't used to them and you aren't very comfortable shooting in general. It's akin to trying to cook sushi if you are still having trouble boiling just rice. Don't overcomplicate it for yourself. Because then you will stress yourself out and mentally and emotionally bring yourself down if you aren't getting the shots. All because you are futsing with a CPL. Also, because your lenses aren't fast, a CPL will make it even slower because the amount of light reaching the sensor will reduce. This then causes blurred movement and/or very high ISO. My recommendation is stay away from the CPL unless there is a very specific need you need to fill (i.e. shot of the bride/groom through a glass window as the CPL will cut the reflection).
Settings-wise, it depends on what you are comfortable with. I shoot full manual, so that is what I am used to. But you may want to set it to Av mode (which allows for you to choose the aperture and the ISO and the camera will auto set the shutter speed), an ISO (say 1250), and let the camera decide a shutter speed. Or Tv (which is shutter speed and ISO controlled by you and the aperture auto controlled by the camera). Play around with what you are good with. And if you aren't comfortable with quickly changing settings (i.e. walking from in to out the church or vice versa the lighting will be VERY different), then I would recommend using Av or Tv. I would also shoot RAW if you are familiar with it, otherwise with JPG you risk the camera screwing up the white balance (especially moving between rooms, buildings, shade, daylight, etc), and then pictures may be ruined and of no use (no bride likes their white dress turned orange or purple
)
Hope this helps!
-Heie