Whatever is more convenient for you. I'm just messing around with the "advanced" settings of Heroes 5 for the second time in my life, so it's "going slowly"...

Added after 15 hours and 25 minutes
Dear Hottabych, a little voila! I managed to create an area for recruiting neutral creatures, namely a manticore. BUT on the map, there is an empty space instead of a dwelling; I assume this is because I didn't: 1. Understand how to work with blocked tiles and active tiles. 2. Take action with MessageFileRef - they probably control the name and description of the dwelling, if I understand correctly. I'm attaching screenshots: https://ibb.co/tP6PnY0 - view on the map https://ibb.co/9VSM5f5 - in the editor