I used custom made french doors with the same profile as other internal doors in the house. Not expensive. Used period hardware consistent with hardware in the rest of the house. Amazing difference.

The doors you are referring to are called pocket sliders. They are very expensive around 180 a pair, although as they're meant for joinery, the cabinet maker would need to fix a 16-18mm jamb and create a recess for them to slide back into, this would effect the opening access of your doorway. I don't think these are the best or easiest solution, however they could be adapted to your needs. Personally, I think the FOC Face of wall sliding door is the best solution, given you have at-least 900mm on either side of the door to accommodate the open door?..if you don't; then, without knowing your house style these may be way off, how about bar doors, the name escapes me the ones in western movies where they're either side and you push through them. I've see them in a solid core door, so at-least they close themselves, and you could teach your cat to nudge through them, so its tidy when they're shut.

I wasn't entirely sure I understood what an authentic industrial style was. It's interesting to know it has particular elements but is not limited only by those same elements, but can embrace other elements or styles. Educational article-thanks!

Sure, please see below. The below is what I was thinking for the bedroom wardrobes and the hallway linen closet (painted white): For the internal doors, I was thinking of one of the below (again painted white - let me know your preferences): This is the more usual style that could be an alternative if it's too much shaker: Note that the main bedroom and linen closet door will be right beside each other in the hallway. I was preferring the shaker style as there is a style that looks the same but with translucent glass in place of the shaker panels which I wanted to use for laundry and bathroom to let in more natural light in the hallway.