So with PS4 mods officially canned, I'm planning on picking up a semi-decent PC in a couple months to access all the modding goodness. My question is whether or not old or abandoned mods will work with the remastered version of Skyrim. For instance, one mod I'm really interested in is http://www.nexusmods.com/skyrim/mods/15725/? but the author is no longer supporting the mod due to real life stuff and working on other mods. Could I download WOTM for the SE version of Skyrim and have it still work properly or would it only work on the original version of the game? If not, is there anything I could do to make the mod play nice with remaster once I've downloaded it (privately, obviously since I don't want to take credit for someone else's work). I fairly computer savvy though I've never worked with mods before. Or would that require files only the original author has access to?

To make mods compatible with SSE they need to be opened and saved with the new CK. That's the minimum requirement. So in theory you could do it yourself.

You can't redistribute mods without permission from the original author but for personal use there nothing stopping you.

can you upload privately?

This has been a controversial topic for over fourteen years. Some contend that it is perfectly acceptable to distribute a mod privately that cannot be distributed publicly. Others say it is just as morally wrong to distribute privately as it is to distribute publicly. We have never come to a full consensus on this issue.

"upload" implies publicly, so no. "Send to a friend" - maybe.

Unless you mail a physical disk to the friend, any transmission method would involve uploading.

Privately distributing to your friends a mod that is no longer publicly available is basically the same as recording tapes or burning CDs for them. So if you're cool with those things, then you're cool with distributing the mod. Record companies, obviously, are not.

Not without permission from the author. Distribution is distribution, no matter how private or public it is.

in theory.. from what I have heard, Bethesda hasn't really done anything to discourage it over on .net

They actually have, plenty of people have been banned for it. They just don't have a wall of shame like Nexus does.