You are using the bigfoot package. Have a look into the manual, you'll get it (probably) by typing
texdoc bigfoot on the command line. The manual has 60 pages and only two explain how to use the package. All the rest consists of the documentation of the 1600 lines of code of the package. To change something inside this machinery will be difficult. So unfortunately you are probably asking something non trivial.
And your question isn't really clear. Do you want to change the sequence of the footnotes only on the first page or for the whole document? So you need to elaborate on what you want to achieve.
Why can't you write your first footnote as a »normal« footnote? Or maybe have three types of footnotes and the default one only for such footnotes that have to be the first ones?!