So a cocktail to go with roasted oysters? My first thought goes straight to something with sparkling wine. Something nice, I am thinking something like a Spritz: fill a flute 3/4 full with prosecco, an ounce of aperol or campari, top with soda water, finish with a squeeze of lemon juice, garnished with a lemon slice.

I'm a total Thanksgiving contrarian. So for a cocktail I'll offer the French 75 which goes back to between the wars and named after a French artillery piece. Components are, gin, cointreau, sugar, lime juice, topped off with sparkling wine (which could be cava, prosecco, champaingne etc.). It's a good thing I don't cocktail anymore. But this will go well with oysters.

How about this:

1 1/2 oz Citron Vodka
1 oz Blue Curacao
3 oz fresh lemonade
Lemon twist to garnish.

You could call it a Carolina 'Blue Point' Lemonade. I was never a bartender, but I think this will mix well.

i would do something involving gin and lemon, like an aviation.

...and be sure to remain upright.