In the latest version of Arduino Desktop IDE, are there all features of Arduino Web Editor?
You will always get the same API features in both, because the API is separate to both of them - it's a plugin that's developed separately.

Would you get the same GUI facilities? No idea. Maybe - maybe not. It depends how useful they would be. You may get features added to the GUI that don't appear on the web. Or you may get the other way around. If they are essential to the operation of the system, though, you will get them added to both.