To get the syntax highlighting and line numbering on thwack, you have to click the "use advanced editor" link above the reply box. This will pop you over to an editor page with more options. It will carry over your in-progress draft, so don't worry if you realize that you need something rom the better editor halfway through a reply. The advanced editor's toolbar has a blue >> button on the bottom right that pops out a menu with even more options. One of those options is "syntax highlighting", which lets you choose from a few languages. Sadly, SWQL is not one of the native ones. So I just pick SQL and it is close enough.
Let me refer the EOC part of that question to derhally.