Each Other os file is specific to that operating system. The Other os you have right now is for Fedora as you stated. But to run YDl, you need to make sure to grab to the other os files specifically for YDL itself. Also if you want to completely remove Fedora and replace it with YDl, you need to clarify to "remove all existing linux partitions" when you get to the install screen. That way, you can be sure that Fedora is non existent with a fresh partition. Or if you want to keep both(make sure you have anough space on the HDD) install in the free space you have in that linux partition.
I can't say how much of a difference YDl will make for you if you were having resolution problems with fedora. Chances are, you'll have the same problem. I can say this because I tried both with no avail in solving res (full screen) problems.