Outlawe

I am currently making a mod pack for M&B: Warband. Some of the mods I have chosen are by creators who are no longer active, making it impossible for me to get their permission to upload their content on the nexus within the mod pack. What are the rules around mod packs? As in, would I need direct permission to upload content of other users in mod pack form? (It seems like a stupid question, but I'm asking it for general clarification). Thanks.