I would definitely recommend doing the valve cover gaskets while doing the injectors. It’s not a difficult job but it is time consuming and there is a considerable amount of overlap in the jobs so it certainly makes sense to do both jobs at the same time if both repairs are needed.
I went OEM with all parts when I did my valve cover gaskets and have zero issues. Some have gone with aftermarket parts and also report no issues so the choice is yours....all about comfort level and available funds.
Several great write-ups available with video/pictures. I basically looked at all of them and had no problems.
Take your time, label parts during disassembly and take pics.
It gives you an opportunity to clean up your engine bay, especially after living with leaky valve cover gaskets.