Hello,
From what I read, you want to develop a browser add-on for the different browsers.
Most popular browsers can add extension via:
.crx file for chrome
.xpi file for firefox
.exe file for internet explorer
.safariextz file for safari
There are application that allows you to develop for multiple browsers from the same source code, for example crossrider.com.
From 1), I guess you're only targeting windows plateform, no ?
The extension can be developped using Javascript, CSS and HTML ... It depends also on which technologies you used for your code.
Retrieve data (2) and update 53) via a remote server is possible from a browser extension.
Please, let me know of other details, or feel free to contact me for questions.
Regards,
Michael