With my heroes, the "contact" feature is disabled; otherwise, it won't be possible to take an army from caravans.

If I understand correctly, the "contact" feature with your heroes is actively used in the Test Environment (quick army transfer, etc.).
At the same time, creatures can be freely taken from caravans.

If we take NCF, for example, it is necessary to create a necromantic table (raising creatures with necromancy) and so on. Some files will overlap. Then there was an idea to rebalance NCF and merge it into one project - EV. But there is no time for rebalancing. I would remove about 70 percent of the creatures from it. But then there will be no compatibility with the original NCF.

And here, the creatures from NCF are not needed. The idea of NCF completely destroys the racial skill of the Union - try to find the right, sworn creatures among a huge number of creatures...
Only the core is needed. There are no new creatures as such; there are only modified copies of old ones. Well, maybe I'll want to create a couple of specializations for summoning some specific new creatures or upgrading old ones to a new, higher level (hello, Gelu from Heroes of Might and Magic III)