muddyknees2000 said:

I could easily see them having both.

As for where a scene like this might fit into the film, I believe it would go right after Luke surrenders himself to Vader. Vader gives the order for the troops to search out Luke's remaining friends, but we never see anything come of it, the very next scene is Han, Leia and company attacking the bunker. It would add more urgency if on the morning of the attack it was shown that imperial troops were attacking ewok settlements, looking for them. You don't even need any of the main characters, just show troopers raiding different ewok villages. One of them could be on a lake as per the mcquarrie concept art, thereby bringing the seatroopers into play

While not in love with the "sea troopers" concept (feels like a ploy for a new action figure to me), this story point is AWESOME, ups the dramatic odds in act three, and makes perfect sense story-wise.