So from a comment on my mod (http://www.nexusmods.com/skyrim/mods/57513/?) I've learned that Requiem changes horse names to My Horse, an doesn't allow my mod to change the name. I assume that they add a new display name for your horse, and my mod changes the display name on the PlayerHorse alias to NONE and unchecked the Stores Text an Uses Stored Text boxes on the horse alias. But putting my mod after Requiem in the load order didn't seem to fix it. I'm going to create a patch, but I have 2 questions:

Why wouldn't my mod overwrite Requiems change? Or is Requiem doing something more complex?

And do I need the author of Requiems permission to create a patch for my mod?

Apparently I don't.

Also, should I have the master 1.7 Requiem .esm or 17.3 or both?

It won't matter since the file still has the same name -- "Requiem.esp" -- as long as the formIDs of things you're editing are the same in either version, which they almost certainly will be.

Keep in mind that if you want to use it as a master you need to flip the ESM flag on for Requiem.esp before you start editing it in the creation kit.