(i) Pass. The spade void is not notrumpy, but it is partner’s suit. Turning to hearts, give partner as little as ♥ xxx and you would rather play 3 NT (four heart losers on a 4-3 split) than 5 ♦ (three losers and down you go). See deal.

(ii) Pass. Without a singleton, to even think of 5 ♦ would be misguided. The diamonds should run nicely in notrumps.

(iii) 5 ♦. Because of the side-suit void, and the “slow” minor-suit holdings. Top cards will need to be dislodged and you may not have time in 3 NT after, say, partner’s one heart stop has been dislodged.