I recently replaced a screen on a 5a. The screen has nothing to do with the data, keys, or OS, unless there was a big messup and other hardware was damaged during the work.
Even though you said DIY, someone else might find the following info useful: One way where having GOS could affect a repair is if you take the device to an Android repair shop. I tried that and when talking with their tech, I mentioned a non-stock OS, and they said they couldn't touch the device. Their response sealed the deal for me to go DIY.
ifixit.com has excellent tutorials and had a good price on the parts I needed.
may your hands be steady.