Is how a proper noun?

Answer 1

No, the word 'how' when used as a noun is a commonnoun; a general word for the manner or method of doing something. Example:

• I see it but I don't see the how of it.

A proper noun is the name of a specific person, place, or thing; for example, the TV program, "How I Met Your Mother" or How Street, Haverhill, MA.

The word 'how' more commonly functions as an adverb or a conjunction; for example:

• How are you today? (adverb: you are how)
• I explained to them how to make the recipe. (conjunction)

Answer 2

No, "is" is a verb used to show existence or identity. Proper nouns are specific names given to individual people, places, or things.