Higher yes, significantly not necessarily.

Didn’t they stop trying at some point because they didn’t want him to be replaced by someone competent?

As I understand it: because not enough people will use it through these ways, leading to not enough motivation for the dev(s?) .

the storm surge could be up to 15 feet

It’s probably because of the last sentence. Which technically is a fact (because they obviously think that), but 5m is something at least cities in northern Germany are usually prepared for.

I’m not sure how exactly the tides are measured and if it differs internationally, but we have floods at around 5m every few years without any significant damage (German source). Hamburg had a flood with 6.45m in 1976 without damage to the city (only the port and other parts outside the levees were obviously damaged; German source).

but an order of magnitude smaller

I’m pretty sure that would be three orders of magnitude.