We must be playing some sort of convention over interference that has become popular in the past 20 years, because I have no idea what was going on.
- Does 3♥ not say anything about hearts?
- Since 3♥ shows 2+ of each minor, would other bids have shown shortness?
- Over 3♥, explanations of 3♠ or 4♠ by me appeared to be identical. Is there a distinction?
- Why did North deny ♣A?
PS: Please get rid of the unnecessary verbiage saying "notrump opener" -- it's perfectly clear that no trump has been opened.