Scenario Creation Obstacles

some of these may be hardcoded or discussed earlier on forums,
nevertheless all of these affect my scenario greatly. So I'll just sum it up and sort questions by letters.

-these are the OBSTACLES and brain teasers I've come up to-

[A] getting goodies from huts only with a one specific unit, (just like air units make huts dissapear)
how to implement that to ground units)
Or in general how to manipulate hut and unit interaction.

[B] only one difficulty level.
starting a scenario you get to choose difficulty from chieftain to deity.
how to disable all levels except one, basically you get only one option to click "ok".

[C] air+settle unit with movement let's say 2/20,
before unit's movement range is about to expire (or "run out of fuel")
simply building road, irrigation or mine, immediately reinstate movement digits to original 20
how to avoid that.

[D] how to forbid units getting promoted to veteran status during combats.

[E] how to enable irrigation away from ocean and preferably from rivers.

[F] forbid city rapid growth through celebrations. Only growth factor - food.