Re the contamination, did you dust off the lids before you opened the can?
The shed paints get all sorts of crap on them.
I think maybe you guys might find adjusting your technique might help. Dont start half way up in the middle of the wall like you see on 60 minute makeover, roll up and down about two roller widths at a time, gently lay off by back rolling and leave the wall with the roller spinning, then roll your next one fishing by rolling just into previous section and laying gently off again. Don't overload the sleeve and dont press hard trying to get every last bit of paint off it and onto the wall, apply with medium pressure and using a short pole is much quicker if space allows.