Thanks Perche for your detailed response and again to obscure2k. The website for Cantina di Vini già Schiavi in Dorsoduro shows that it's closed on Sundays, and I checked directly, and sadly they will be closed on Easter Monday as well. There's a lot of contradictory information online about the opening hours for bacari, which makes it challenging to plan. For example, some sites show All'Arco closed on Sundays while others say it is open daily. This doesn't take into account that Easter Monday is an official holiday! After reading through these threads, I feel like I have some great ideas for where to dine, but I'd like to ensure that those places will be open AND that there will be availability. As I mentioned, we do have reservations for Antiche Carampane as well as Al Covo during our stay. I tried for Alle Testiere but they were fully booked. I'm now getting more concerned about eating on Monday, so thinking that we'll check out Harry's Bar then.

The following aren't mentioned as often as the 'greatest hits' places, but I've seen some/enough positive comments. Would love your feedback on any/all!
Estro
Osteria Ca' del Vento
CoVino
Osteria Santa Marina
Ai Promessi Sposi

Would either of these be appropriate for our family of three (as opposed to a romantic meal)?
Da Fiore (in San Polo)
Corte Sconta

Grazie mille!