I found several other bugs (besides the ones introduced by the Squirrel changes):
1. tinymce not able to display the fonts from google, squirrel
2. tinymce not able to recognize/select automatically the font when clicking on a span that has it.
3. issues with google and squirrel font displays in fontmeister setup
4. other small issues (had to quotify fonts in more cases, added several improvements, etc)...
I managed to solve almost all of them. The changes are so extensive that cannot be put here.
Sayontan, I can give you the modified php file and you can compare/change if you want to update. Let me know and I can email it.
The fixed php file has all the above, (no 2 still has a problem with recognition of fonts that have ! or numbers in them, but I think is tinymce issue). Of course, one still needs to modify the squirrel css files manually to account for the name changes and specified paths.