As long as there is theoretically real hardware to run your submission. The size of the emulator obviously doesn't count, as it is just used for convenience.
This is a good question. Although you absolutely should include license files in your final submission, they are not crucial for the game to run and are mostly just a notice "Hey I use this and here is the document saying that I can". Depending on the license, I would maybe just include the copyright notice in the game and wouldn't count the whole license text.
Everything that needs to be shipped with the game for it to run on a clean installation of windows/macOS/Ubuntu/... The rules clearly state that this limits only the disk space.
Although, Edge/Chromium comes in stock with Windows. So it technically doesn't count, you can make a browser game. Because this jam is inspired by .kkrieger however, it may not be as appreciated.
The size counted is the .exe + all the assets with it, unpacked from a .rar/zip. If you use any compression, it has to be decompressed by your program itself. Hope that makes sense.
The wording on the itch page is rather confusing. You CAN use anything you want BUT you have to count in the runtime size too. You need to count everything that is needed to run the game (excluding stock OS stuff).
You can, but remember that on systems where python isn't present by default, the size of the python runtime counts too. Luckily, AFAIK python is installed by default on e.g. Ubuntu.
It depends for what version is your game compiled, the latest downloadable JRE is JRE 1.8. Every version after that requires the programmer to build his own runtime via jlink
I would start with SFML, it offers a great documentation, community forum and tutorials. It is also very simple. It supports only 2D rendering tho. (And can port OpenGL but that is only the window creation)
