You are SO helpful! Yes, clearly an Echinopsis (now that you tell me). I will carefully consult the Echinopsis FAQs you linked to. By the way, I love the Liffle Encyclopedia of Cacti to which your species names link, particularly the way it organizes and presents information in the species descriptions-- It is by far the most useful resource I've found. No, I've seen no flowers, but I'm also not watering, on the assumption that all these specimens in dormancy.

You might find this site interesting:

https://old.reddit.com/r/whatsthisplant/

My last three unidentified cacti, with thanks in advance for your immensely helpful expertise:

Walter, they should be coming out of dormancy now, so watering them isn't out of the question - in fact, it should be started (assuming you're in the Northern Hemisphere).

I'm throwing out a WAG on #1 - another Echinopsis, #2 a Mammillaria, and #3 a Parodia, but without flowers, it's difficult to say for sure. Kara's a lot better at this than I am, so perhaps her working of wonders will wow you again.

Thanks Jeff, but you’re not too shabby at iding yourself:).

ok for #1 my brain goes straight to Echinobivia ‘Rainbow Burst’

#2 Mammillaria spinosissima rubrispina aka red headed Irishman cactus.

#3 not sure, but I agree with Jeff probably a Parodia. When it flowers post pics:). Post pics of your second cactus from your original pics because I‘m curious and flowers will totally help:).