I'm considering revisiting D2 and I loved playing the Eastern Sun mod for no other reason than it took me away from the vanilla experience. I've since found several other mods and was curious if I could combine them together, and if so, how I could go about doing that?
It depends on how the mod files are structured. Most of the time with D2, you replace the patch file, and that replaces patch 1.13 with whatever mod you have.
If both mods function like this, it would be impossible to install both mods at the same time.
There currently is no Diablo 2 installer that allows for multiple instances of the patch file to run together.