iRule v11 to send user to correct DC database based on HTML header

HTTP::redirect https://2.2.2.2[getfield [$host] ":" 1][$httpuri]

i do not think you do need host part.

HTTP::redirect "https://2.2.2.2$httpuri"

additionally, i think it may be better to not use string tolower for uri in case server's uri is case sensitive.

Since I am trying to put the actual VIP IP address in the HTTP::redirect, would there be a way to strip it out once it reaches the other DC LTM? And also not have the client see it?

that is why i think HTTP::retry could be a good candidate because bigip does retry to another bigip by itself. anyway, i understand you want to use internet bandwidth rather than mpls one.