I am aware of fact that IP doesn't get listed as standard dimension in standard reports or workspace. In Data Warehouse, IP does get listed but no way to transform into meaningful information like company.
Does Analytics support analyzing traffic hits based on IP ranges?
What is great about classifications is that once applied it would handle real time results... they look back and allow you to use against realtime data. The key here is for real time reporting is only variables or events are able to be shown in realtime.
External integration I know of none.
The challenge you will find is for "new unclassified data" even if you update it every minute can still have a multi hour time to populate data back end. I would say if your site is typical to most digital web sites the bulk of your traffic is from regular users whom you can identify quickly from present historical. The newer users over time will also fall into that category pretty quickly I would say first few months. Its just a matter of managing expectations in reporting and developing a short and long term strategy to add the new unclassified IPs.
If you pass IP address into an eVar or prop, you can do whatever you'd like with it in Adobe Analytics, including classifications. Unfortunately IP address does not support IP address by itself.
In terms of 3rd party integrations, these would not be supported either unless you fed that external integration a Data Warehouse report or data feed. I'm not aware of any integrations that do this, though.