What is idiomatic and what many consider good style differ.
It possibly is idiomatic in informal, spoken American English to use only the preposition required by the final noun.
He has interest and respect for the law
may be acceptable. I believe I have heard that kind of abbreviation in educated American speech, where people can lose track of exactly what is being said, but I also do not believe that I have heard it frequently because people do not try for that kind of concision in speech.
He has interest and respect in the law
is plain weird.
The comment by Gary Botnovcan reflects what I believe to be the only expression acceptable in formal written English: what is joined by the conjunction are noun phrases, each consisting of the noun and the preposition appropriate to that noun.