I have a few questions on appropriate folder structure in cucumber:
I think I am going to organize my feature folders according to type_of_user/type_of_feature.feature, i.e. main_admin/add_a_customer.feature or franchisee/schedule_job.feature. The only slight issue with this is that of the user types I have: cleaners, customers, franchisees and main admin/franchisor, the latter two users share many features. For example, both franchisees and franchisor have the ability to add new customers and schedule jobs, the only difference being that the franchisor has the ability to schedule a job for anyone, anywhere - i.e. the only real difference is permissions, not functionality. Does it matter that I will be essentially duplicating tests for these two users, given the proposed folder structure? Or should I be looking to seperate folders by functionality only, then type of user?
For my mobile app, should I have these feature folders separate from the web app or should these go in the root as well: mobile/ios/cleaner_login.feature, mobile/android/cleaner_login.feature etc?
Regarding user types:
Organizing at the top level by user type has worked well for me. However, I would only consider user types separate if they actually used different features, not just if they differed in permissions with respect to specific objects as in the example you gave. You could consider both franchisees and franchisors "administrators", make a top-level folder for those, and just write scenarios for franchisees and franchisors for features that had different permissions for those roles.
If you're a developer and writing RSpec specs in addition to Cucumber features, you might even just write specs instead of features to cover the difference between franchisees and franchisors. (I would only do that if the differences between franchisee and franchisor were fairly trivial and not worth exposing in Cucumber.) If you're QA and testing only from the outside of course it'll all have to be in Cucumber.
I would certainly not systematically duplicate entire scenarios for the sake of any organization. The extra work required to maintain the duplication and the errors when you forgot would be far worse than the bit of extra work required to follow a slightly more complicated system that minimizes duplication!
Regarding web and mobile: How to handle different platforms depends on how different they are.
If you have a web app and a native (Android, iOS) mobile app the step implementations will be completely different and your tests will need to be in different projects altogether. That probably won't mean that much duplication, since the users and features in the web and mobile apps will probably be rather different.
If you have two web apps, one for desktop and one for mobile, there are no technology issues. But again it will depend on how similar the two apps are. If they're different, separate them at the top level (even before users). If they're very similar, separate them only when necessary and only at the scenario level.