If you are running the 4600 derailleurs, why replace them if they work well? If you are keeping the 4600 STIs (brifters, levers, whatever term you like) then why buy anything new? As far as I can tell, according to the Shimano chart, ythe 4600 STIs should be fine with the 7000 brakes .... so get the good brakes. If you start swapping derailleurs, you might end up with further compatibility issues.

Above someone said it was 4700 when Shimano adjusted the cable pull on the Tiagra group .... which is why I don't recommend older Tiagra even though it works well .... you are stuck with the brifters and derailleurs, and if anything breaks you need to replace the whole lot. Since you have 4600, use it until it is used up.

I am not sure the 4700 derailleurs are any better, just that they were redesigned to match the other series' cable pull.

Please keep in mind, the only thing I am an expert on is being wrong.