I loved the joke at the end!
As a mild suggestion:
I think an option to make it a Defensive Ice Typing would be to give it a secondary typing.
Since it is weak to Rock, Fire, Fighting, and Steel, I can suggest Steel typing, seeing as it lives in the edges of mountains and isn’t afraid of Rocks, it would be suitable for it not to be weak to Rocks.
Having wings means it won’t be a Ground Type, and while it could be Rock based on its nesting I doubt that would give it useful resistances.
It nests at the edge of sharp cliffs. It spends all day carrying food to its awaiting chicks. | |
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As for Empoleon whom is also a Penguin, it is Steel, and the real benefit to Delibird is It removes SR as a weakness, and both the Steel and Rock weakness as a whole.
Pokémon Sun Pokédex:
“Although it naturally prefers colder locales, Delibird in Alola seem able to withstand the heat to a certain extent.”
I could see it with a Fire resistant ability like Thick Fat, which could help its Fire weakness, reducing it back to 2x.
With your suggested Filter, however, that is probably better overall.
The only other thing would be to give it Levitate, similar to how Flygon has Wings but instead of being Flying it has an ability which makes it fit the flying theme.
The justification would be that unlike Empoleon, Delibird actually does fly and even helps Rock Climbers.
Black / White pokedex
“It carries food rolled up in its tail. It has the habit of sharing food with people lost in mountains.”