(1) What difficulty level and version of Wesnoth have you played the scenario on?
medium, 1.6
(2) How difficult did you find the scenario? (1-10)
7 to survive
9 -without losing most veterans
10+ -without losing your allies.
attacking: ~7
(3) How clear did you find the scenario objectives?
clear
(4) How clear and interesting did you find the dialog and storyline of the scenario?
Not much talking, but not that clear, it sounds a bit like Kapo'e wants to attack.
Storyline is straightforward until that other human arrives.
(5) What were your major challenges in meeting the objectives of the scenario?
Extremely strong reinforcemets for my enemy (troops + gold), stupid allies.
In my first attempt, I recalled all veterans I had and mainly tried to hold the outer wall with some attacks at night. Around turn 15, I had to retreat to the inner wall and in the end, only Kapo'e, Grüü and a warlord, that was recruited as grunt some 15 turns ago, were left and I had no gold.
In my second attempt, I played more offensive in the beginning, defeating the first wave, and retreated earlyer (~ turn 12). This way, most veterans survived (but still hardly any gold left). Only problem: when I retreat, my allies don't join my in my center castle, but go for a mad dash and, of course, die.
Third attempt: recalled every veteran I had in turn 1, using center and wall keep, spent all my gold the second turn using two wall keeps and rushed, attacking at dusk. By turn 6, Lanbech made the deadly mistake to attack personally. (If he would have retreated towards the arriving, he may have won.) => not many losses, some leveling, allies living, 400+ gold.
(6) How fun do you think the scenario is? (1-10)
6. really challenging
(7) What, if any, are changes you would have made to the scenario to make it more fun?
Cleverer allies

or maybe put their base inside the inner wall?
And, I think, just the troops without gold would be enough reinforcement for the enemy.
(8) Was there any event that caused you to lose the game and forced you to reload or restart the scenario?
Loss of many veterans, see (5).
(9) If you know a bit of the Wesnoth Markup Language - do you think that the WML of this scenario is clear and well commented? If not which part would you like to be documented better?
N/A
EDIT: third attempt