The only extensions that are not CF compatible are the very latest ones... such as Digital File Pro 2. CSS Form Builder and CSS Sculptor 3 are not explicitly supported, but as far as I can see don't generate anything language-specific that would cause you a problem on the other languages. I have used a CSS Form Builder form inside a CF site and the only real difference was the way I chose to process the form.
If you ever decide to program PHP and need any help, please let me know here or shoot an email... I was in the same situation in you, in that I used to program ColdFusion exclusively. I thought it would be difficult to make the move to PHP, but now after doing it and saving a lot of money in server licensing, I am glad I have made the switch. It also seems like the support community for PHP is quite a bit larger.