Please don't take it the wrong way, since it's not meant nastily/meanly
You might want to tell people a bit more about what the Mod involves-- the basic idea seems pretty obvious, but are you planning quests, characterisation, custom meshes, et cetera? The more info you can tell people will (usually) help you get the right people involved Also, you might want to show what you've got done up to now-- a lot of people are generally 'unwilling' to help with Mods they know little about-- plus, if you show you've got something, it'll show you're serious about this (Trust me, as a Mod Maker myself, I've had like a thousand ideas I've started, and then scrapped after a week or so, and most other Authors have either been there, or know people who have.)
Personally, I'm probably not good for helping you, haha, I'm pretty much a lone-wolf when it comes to Mods, until it comes to what I can't do But yeah, from experience, even getting people to make small bits for you can be hard, because the people who can usually have their own awesome projects to work on.
although, as a DW fan, I'm curious! What sort of Followers are you planning? The Doctors themselves, or just Companions? Are you going to do Classic Who, or just Nu-Who? If you're working on Companions, I think story-oriented people would be useful, maybe? For characterisation?
Anyway, good luck