North will open 1♥ and south will bid either 1♠ or 1NT (if playing Kaplan inversion). If 1♠, I think North has an interesting decision whether to respond 1NT or 2♦. Personally I like 2♦ because of the 2 card spade suit. It will then be more likely to be able to play in 2♠ when it's right. The other problem with 2♦ is that you will often play in 2♥ when it's wrong. Personally, I don't mind either bid and they could each work out given a different hand in the South.
After a KI 1NT, North must now bid 2♦ and south will probably take false preference with 2♥. On a good day, North will have 6 of them. Unfortunately, today wasn't a good day.
After my proposed auction of 1♥-1♠-1NT, south has an interesting problem as 2♣ will often be artificial. If that is the case, I can see pass being a good alternative to bidding. But that is probably just me masterminding the auction seeing both hands. I'll let the others comment on how they bid it at the table.

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