The only times I've seen games featured in museums as an interactive exhibition is through arcade machines or a console they've put a racing game on to go 'wow, remember the x-box 360?'. The only exhibition I've seen with games as a medium for art is the LuYang Arcade
(though I think the artist does NFTs these days, sigh). This is mostly through the utilisation of the aesthetics of games or the themes of power, defeating enemies, or uncovering information that seem inherent to many classic game genres. The whole exhibit is a means to provoke confusion about limiting things to binaries, as well as to express some deep emotions about gender and the human body. Not the most relevant, but perhaps interesting.
4. In terms of this exhibit, the most easy-access, intuitive coding language I know is Scratch, and that's by design since it's meant to teach children. I don't know at what point it limits a game's capacity, but I grew up on the scratch website and some people made great stuff.
3. I would definitely decorate the gallery, even if it leans minimalistic. Maybe utilise flowcharts and other graphics representing the process of making games?
6. I feel like you want a good mix of interactivity and substance you can access without that interactive element, just to keep things flowing and engaging! Not everyone wants to interact, and not everyone wants to simply look.
In terms of 1, 2, and 5, I think the biggest factor would be your angle on games as art. If it's something we've heard before, it won't be as interesting as if you have a way of looking at it that opens up new opportunities for both the medium and the artist. We know that games are unique for their interactive elements, but what else allows us to get a unique perspective on a piece of art? Is it their relationship to time, to process, to 'work'? Is it because games are dependent on the player, and to what extent is that true? Can you remove the player's control to access a new level of meaning, and when does it stop being a game and become a video? Maybe you don't want it to be quite that intense for the average audience, but maybe you don't want it to be too surface-level either.
I know an artist who loves experimenting with medium and form, especially deconstructing the medium and the art to create something new and exposed. I think the opportunity to see the bredth and depth of a new medium could be very engaging for artists like him.
I'm not sure if any of that was amazingly helpful, but it's likely food for thought if nothing else. Good luck!