Our vacation plans (late Sept./early October) include four nights in Bellagio (Hotel Florence). First dinner will be at the Florence because its restaurant closes for the season the next day and I had an excellent meal there last year. Based on my own experience with Bilacus and recs from Fodorites, the other three candidates are most likely:
Bilacus
Silvio's
La Punta
Are any of these closed on Sunday or Monday night? Which would you pick for the last night (Monday) to end a stay in Bellagio on a high note? La Punta is the wild card; I've heard the least about it, but it seems to be good. We will have a car, so no worries about taxis or after-dark walks.
Thanks!

We also enjoyed Trattoria San Giacomo, right across the street from Bilacus. I believe it's also mentioned in the One Week in Bellagio trip report. Buon Appetito!

I would choose Silvio's, if it's open. Its specialty is fish from the lake, of which there are two kinds: a small sardine-like fish and a fish that is in the trout family.

Bilacus and Silvio were open on Sunday night in May. Bilacus was closed on Monday, Silvio was open. Haven't eaten at La Punta. I doubt schedules would change before mid-October.

Personally, I don't care for the taste of the lakefish and have overall not been impressed by the food at Silvio on two visits but lots of others love it.

The most impressive part of our meal at Silvio's was the first course of simple spaghetti with the freshest tomato and basil sauce imaginable. I never knew plain old spaghetti could be so wonderful. We liked the fish too, but that spaghetti has me drooling when I think of it.

We tried to get reservations for any night at Bilacus upon our arrival and couldn't. They were fully booked for our entire stay. Our hotel tried as well, and we stopped back to see if they had any cancellations. No luck.

I assume you know to ask for a table outdoors at Bilacus.