Fwiw, Scalini Fedeli doesn't strike me as the kind of restaurant to go alone or with a buddy. No hotel is going to be conveniently located to both the Met and Scalini given their locations, but if you stay anywhere on the east side (or at least near Fifth ave.) from midtown east to the Gramercy/Flatiron district to the east village, lower east side to Soho (small walk) and the financial district, you can easily take the subway with no transfers.
The Royalton is ok. Rooms are small and the whole place is dark and they have no outdoor space. I think it's fine in winter but spring/summer, not so much. At ~ $400/night, I think it's too expensive, but if you found a deal, maybe.
www.oyster.com/new-york-city/hotels/royalton/
I'd rather stay at the Bryant Park for about the same rate where you have big windows, some facing the Bryant Park and the park across the street.
oyster.com/new-york-city/…
The Setai on Fifth & ~ 37th st. is new with Ai Fiori restaurant inside. (I've had lunch there and wasn't that impressed but it gets great reviews)
oyster.com/new-york-city/…
The Strand is also newish and around the corner from the Setai (just off Fifth) with a rooftop bar and nice big windows.
oyster.com/new-york-city/hotels/the-strand/
The London which is a stone's throw from Le Bernardin is all suites with the Gordon Ramsey (who's no longer associated) restaurant.
oyster.com/new-york-city/…
You might want to consider the Gramercy Park/Flatiron district (near Gramercy Tavern and Eleven Madison Park) where you'll find the Gansevoort Park Hotel ($392 on tablethotels.com and booking.com)
oyster.com/new-york-city/…
The Giraffe, a bit older but known for service and a cute rooftop bar and less expensive than the rest at $356 on booking.com and elsewhere.
oyster.com/new-york-city/…
As for hidden Brazilian or Cuban restaurants, nothing is hidden in NYC although there are some great ethnic restaurants outside Manhattan (Brooklyn and Queens) that some might consider "hidden."
menupages.com
lists lots of options for both and does include Brooklyn now. I hear Malagueta and Favela, both in Astoria Queens are very good. But for a weekend lunch, you might take a trip to the Brooklyn Flea market where you'll find all sorts of tasty morsels.
http://www.brooklynflea.com/markets/