Patches can be merged, but things always get more complicated when dealing with ESPs that have other masters than oblivion.esm. Merging too many files can also cause load order problems, as some mods need to load early and some need to load late. So you should also consider that when merging mods. Another problem is that many mods are constanty updated, so if they are merged you need to update the merged file regularly. As for you remaining questions: Spawn rates: check out this mod. Personally I feel that in the wilderness there should be a short respawn time and in ruins and forts a long respawn time. With this mod you can adjust that to you liking. I haven't tested it personally, though, since my current game was started way before that mod was released. As for epic mod, do you have Windfall, Kragenir's Death Quest and Bartholm?