This is a disaster. Why would you want to create such a complicated system? node.js has a bright future and will be able to replace languages such as Python, Java, C#, etc. But why do two back-ends when you can do one instead?
If you're starting from scratch, you can choose a cleaner setup. But if you're dealing with an existing site, you have to figure out if and how you can migrate all the existing functionality. For any non-trivial case (or one with a realistic budget), you're not going to be able to just do a re-implementation and single cutover.