I'm not native of English, so I have a question.
I believe 生憎様 in the last panel contains some ironical feelings. Does the translated phrase "frightfully sorry to disappoint you" have such ironic meaning?

Yep. The word 'frightfully', in this case, is an exaggeration which makes the statement sound sarcastic instead of sincere.

I see. thx glasnost.

Patchy: You're a girl, aren't you?

Koa: For now.

O___o

If this is what's really being said, I am worried about the implications.

When I translated 一応 as "for now", I was actually thinking of the "wipe your face" part, but I guess it came out pretty confusing.