Cloudflare has generally focused a lot of European traffic on the German datacenter recently, so I wouldn’t be surprised if that is simply the routing for now, particularly for free plans. You can also check it at https://cloudflare-test.judge.sh
That’s not the full page, but it would seem as if Business plans are routed via Sofia, lower plans not or only partially. So yeah, Sofia is operational and working.
Peering - Why don't I reach the closest datacenter to me? addresses this as well. This is a mixture of your ISP’s routing, coupled with Cloudflare announcements. As mentioned earlier Cloudflare has focused a lot of traffic on the German PoP recently, so it’s not too surprising, but if you want any sort of guarantee you’d probably only get that on Enterprise I am afraid.
Yes, it is running and based on your data apparently working from Business onwards. The more expensive your plan the more likely that you get IP addresses with “guaranteed” routing, but a tangible guarantee you’ll only have with Enterprise I am afraid. Everything else is best effort.