combining two redirect irules

That looks fine. When including multiple redirects in a rule, or multiple rules for the same VIP, you just have to make sure that two redirects can't be issued for one HTTP request.

You can combine the else and the following if to simplify it:

when HTTP_REQUEST {
   if { [HTTP::uri] eq "/application.aspx" } {
      HTTP::redirect "https://www.google.net/application.aspx"
   } elseif { [HTTP::host] equals "google.net" } {
      HTTP::redirect "http://www.google.net[HTTP::uri]"
   }
}

Aaron