AppleTV + External HDD + Projector + 3rd world internet?

I’ve read everything I can find on all aTV products, but need some knowledgable folks to weigh in. Here’s our situation:

We’re ex-pats living overseas and are looking for a means to having an AppleTV connected to a projector (no TV screen available). I’d like to connect our external HD to it, due to the fact that internet is extremely expensive (and notoriously unreliable) here, so streaming and such is completely out of the question. Our 1TB external HD has tons of movies and TV shows already on it, but our current solution of hooking up HD → computer → projector whenever we want to watch something is getting old, and when the kids want to watch a movie while I’m working, makes things difficult.

I’m thinking of grabbing up an old 1st gen AppleTV as it seems easy to connect the HD to it. I don’t need to stream/download directly from iTunes to the AppleTV (did I read that that’s no longer possible after iTunes 12.?) But, I want to make sure that this scenario can accomplish what I’m intending. Can I remove the HD periodically to add new movies/shows to the HD and then reinsert into the AppleTV? Is there another solution that would be better?

My apologies if some of these questions seem juvenile or not well thought out. It’s difficult, expensive, and time-consuming to get equipment sent to where we’re located so I can’t afford to just buy it all and “try it and see”.

It’s going to be difficult using apple products. Buy a Zidoo model that supports internal hard drives.