Both squeezes are legitimate. On the defense where 2 rounds of ♦ are cashed followed by a ♠ LHO is stripped down to ♦Q ♣KJx, dummy has a trump and 3 clubs while declarer is down to ♦9 ♣AQ10. LHO is thrown in while dummy pitches a club.
When 3 ...
I haven't run a simulation but tend to raise. Bidding 2C creates a problem when partner has 5 or 6 hearts and a fit for diamonds or clubs. You may end up in 2m instead of 4H.
Playing in the minor requires making 2 more tricks than playing in ...
What about regional pair events that are stratified? The top strat is open but other strats aren't. Is that open, open+, basic, or basic+? I would assume at least open but can easily see an argument for basic+.
In fact, all 3 of your jacks could be wasted but I would still invite. The ♣J10 could be working as might the ♦J952. I do prefer going through 2♣ and stopping in 2♠ but given that's not an option I'm fine with rebidding 2nt.
Easy to miss a good contract or a chance to push the opps higher by passing. Simple sequence might be 1♥-1♠-2♣-2♥ by opps. Do you get in after passing? You could easily have a part-score in any of 4 strains and not be able to beat ...
I would always compete once partner took any action.
Here's a slightly different scenario with the same hand. I'm over the 1♠ opener. The auction proceeds 1♠-p(me)-2♠-p-p to me. I am very likely to balance if partner doesn't hesitate but with a ...
There is another consideration. Declarer holding Kxx opposite AJT9xx will get an extra entry to dummy when Qxxx is held over the dummy.
A low club to the 9 must be ducked by Qxxx. Use that entry for some purpose and repeat the finesse. Again Qxx must duck to hold ...