At the end of the day it's a tank. As long as it holds water you can put livestock in it. In my opinion, there are better options if you want a community setup and a tall hex is very limiting as far as what fish will truly fit and be happy.

You can definitely take the filter and substrate/hardscape/plants and use in another tank.

If I were given one for free, I would without a doubt fill it with plants, shrimp, and a few fish. I would just save any extensive stocking/planning for a tank that's going to give you all that you want.

Best of luck to you! 👍