Regarding that damaged spoiler. It could've been due to secondary flow of water after impact rather than initial flow. If at impact water was pushed away from under the wing there would then be a reversal toward the wing. Also possibly a wave might've done that. The spoiler was made to take forces from the front, who knows what it was or wasn't capable from the rear. Significant strength from backside forces probably not a requirement.
Would have to take exception to that, built pretty tough from the pictures and the design condition. Wouldn't be much weaker in the deployed, reverse flow case. The spoiler was yanked out by it's roots, and would most likely be a consequence of high rate of descent impact.