"What about internet options dialog. It can be accessed from control panel. Will this still be available?"
as Eric said, mindst yes. It is even present when you disable IE via Settings > Apps > Optional Features (or via PowerShell). Some of the features have been integrated (not moved) to Settings App (Proxy settings).
Kenneth van Surksum as a technical consultant I suggest our customers to uninstall IE, next to some other deprecated features from all servers and install Edge where needed and make it default.
It is not much of work to enable the feature again. The reason why MS does do this is that some applications won't run as expected with a removed / disabled IE feature but it is a pretty limited set for most. Testing is key.
As of today the Edge IE mode does need the IE enabled. I have asked Sean Lynderday about if this is going to change. His reply: Wait for June.
This sounds promising, seems like they have some internal testings on this. I would greatly appreciate if a disabled IE feature would not be needed in future. So as Sean said: lean back and wait.