Mod Organiser + TES5Edit Modding question

[AfriCanuckinOz]

Is it possible (i.e. will there be no disastrous consequences) to:
1. edit a mod in CK (via MO), say, add a new outfit using the mod resources and equip this outfit to a few NPCs;
2. use TES5Edit (also via MO) to overwrite this aspect (the outfit from another mod) in a mod further down the load order that does other imoportant NPC changes (e.g. the look of NPCs).

Will this work? I get the message that this will add the file as a master - does this amtter?

Thanks