If I were you though I would have stayed in 3.1.9 waiting for the next 3.1.11, since 3.1.10 introduced issues with custom profile fields (and not only) that's what you surely would like to test there, I guess.
An option it's to find and apply all of those patches for and on 3.1.10, the existing ones and the futures.
About a bbcode reparser for 3.1.x, I posted here:
About seo URLs, I don't have enough info therefore I can't help you about. I mean tech details.
For sure the extension writers forum it's the right place where to seek help, if you need.
And thanks for the heads-up.