Are you sure about this? Does Electrum have near-instant address importing, and a feature to call a script/notify in some way?
I don't know about address importing but I think it is fairly quick. It does have a command line so it will work with scripts. I'm not sure about notifying.
Even if it does, there are other concerns. IIRC Electrum uses its own nodes and its own query structure and doesn't simply connect to Bitcoin nodes as some SPV clients (which is what I am trying to achieve).
Electrum uses servers that volunteers setup which use bitcoin core as the backend to connect to the bitcoin network.