I have painted several steel doors and never removed the moulding and glass. Why ask for problems? A steady hand keeps the paint where it is supposed to go, and a quick rag or your clean finger removes any that may go astray.

I would say thermally broken aluminum with a 3 coat Low-e (i.e. Low-e 366) on the glass.

Affordable, Black and Impact Rated are not often words used in the same sentence. What type of windows (casement, dbl hung, etc.)? Installed price or windows only? Region of the country?

If the OP had been really happy with what their designer had recommended they would not have posted the question here. Designers are always happy to try different things in other people's homes! They can add an extra photo to their portfolio and they don't have to live with the results! I think OP is looking for validation to stand up to the designer ... just the vibe I got from the question.