With a recent software update, the default editor changed. You can access the old editor by clicking a switch at the upper right above the text input area, here:
The new default is now a ‘rich text’ editor (like Microsoft Word), instead of a plaintext editor with markdown alongside a WYSIWIG view. I can understand the motivation behind the change (official announcement is here), but personally I prefer the old ways.
Whichever version you select will persist across posts.
This isn’t true, I’m not sure what you’re doing wrong (and I notice you’re suspended so it will be a while before we find out), but you can quote from one topic to another in exactly the same way as before.