Those would work too. The problem with regular ice cubes is that they just melt too fast and dilute the drink too much. The big ice cubes stay colder, longer, and they melt just a little bit. That little amount of extra water actually makes the whiskey taste better. Your choice of cherries is ok too, but if you don't mind springing the extra money for a jar of Luxardo cherries you'll really be living it up!
I came here to say black olives are fucking gross and I love olives. On top of that olives, especially these, do NOT pair with lime and margarita. So my remedy which you have already stated are Luxardo Cherries. They are a candied cherry and very dark in color and are the best cherry to add to any cocktail, but truly sing with bourbon based alcohols, IMO. WARNING! they are expensive af, especially if you are used to shitty maraschino cherries.
Luxardo, Gourmet Cocktail Maraschino Cherries 400G Jar https://www.amazon.com/dp/B011PK0CFQ/ref=cm_sw_r_cp_api_i_DG0NFbARPA6WV
They’re also those nuclear red cherries and not the better tasting cherries.
Luxardo Cherries - Anybody that hasn't had this cherry yet is usually amazed when they get it.
Apple Bitters - These are my favorite apple bitters, they can make any drink have a hint of homemade apple pie added to it.
On the cheap end I like the other suggestions here for Vermouths. On the cheap end Boissiere brand is really nice. Depends on your budget. On the high end the best Vermouth I've ever had is Atsby Armadillo Cake. Good luck finding it in person, shop online if you can't but there isn't much time left.