How to map unmatched routes with ingress on GKE - kubernetes

Question

I'm trying to automatically provision a loadbalancer on GCP by using the ingress object with our GKE cluster.
I have three GKE deployments and each is available with a service on port 8080 with a unique nodePort.
When using ingress-fanout.yaml, it creates 4 backend services instead of the 3 specified in the yaml. The 4th service defaults to all unmatched routes. I assume the 4th service is because we don't match unmapped routes in the yaml.
How can one map unmatched routes to one of the services? Is that possible?
Here's ingress-fanout.yaml
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
name: fanout-ingress
annotations:
kubernetes.io/ingress.global-static-ip-name: "our-static-ip"
ingress.gcp.kubernetes.io/pre-shared-cert: "our-ssl-cert"
kubernetes.io/ingress.allow-http: "false"
nginx.ingress.kubernetes.io/force-ssl-redirect: "true"
spec:
rules:
- host: our-website.com
http:
paths:
- path: /*
backend:
serviceName: li-frontend
servicePort: 8080
- path: /backend/*
backend:
serviceName: li-django
servicePort: 8080
- path: /notifications/*
backend:
serviceName: li-notifications
servicePort: 8080
Update: I removed many of the original questions and narrowed the scope of the question. When health checks started succeeding, that cleared the old issues.

Answer 1

First of all, "backends" have nothing to do with the "paths" you specified. "backends" on GCP Console are pointing to your GKE node pools.
Ingress supports adding a default backend. You could have tried just searching for "ingress default backend". You can find documentation about this here: https://kubernetes.io/docs/concepts/services-networking/ingress/#single-service-ingress
Basically doing this will set a default backend when nothing else is matched:
spec:
backend:
serviceName: testsvc
servicePort: 80
rules:
[...your stuff here...]