At the time of this event, Amy's IP address was 172.58.96.230
Probably a misnomer proxy or something.
You can't hide from history though.
The last time Amy connected to Boss Battles before today was June 14th, 2015. At that point in time their IP address was 99.112.16.211
The address 99.112.16.211 has been used to connect to Boss Battles on multiple occasions between 6/14/15 and 5/19/2012, leaving before that only a sole instance of the address 108.90.110.207 on 12/31/2011. So in other words, Amy has been on 99.112.16.211 for over three years and is probably a good base to know them by.
So in other words, this is Amy:
I'm only getting started, let's look at BlockGirl.
BlockGirl first showed up on the 1st of April, 2015 with an address of 66.11.247.81. At this time they were know as 'FishOilTablet'. This address only lasted for a few days, and was replaced by 98.143.5.72 by the 3rd. From here on the address continues to change every few days within the same set of addresses, implying he has a dynamic IP address.
In July of 2015 they briefly used an IP address within the NuclearFallout VPS address space, which implies they were using a VPS as a proxy. 74.91.113.43 was the server address.
Today he logged in on the IP address of 98.143.2.150, which is in the same set of addresses mentioned earlier, and is therefore probably his home IP. So this is BlockGirl.