Minning the swamp will work, but there will be 2 problems. #1 theres no way to "make" a swamp, so the canal sites will have to be swamp, and #2 if someone accidentally forgets and clears the swamp, then there's no way to make that canal ever. We could do minning forest though. You can both make a forest and destroy a forest so you just have to "prep" canal sites by making them a forest first.
Huts just give players unfair advantages. Also they are used to conceal cheating by giving yourself bonuses only when a hut is triggered. They can unbalance the game in both directions, since about the only way to get killed at the start of the game is to get barbs in the first hut which can happen, and I dont really want any complaints for a restart.