node-kubernetes | Node Kubernetes GKE | GCP library

I'm new to DevOps work and am having a though time figuring out how the whole final architecture should look like. My project currently runs on a single Kubernetes Cluster and a single node with a single pod, in the very common Nginx reverse proxy + UWSGI Django app. I have to implement a scaling architecture. My understanding is that I should use an Ingress Controller behind a LoadBalancer (I'm hosted at OVH, they do provide a built-in LoadBalancer). The Ingress Controller will then distribute the traffic to my pods.

Question 1: if my Django app listens on port 8000, setting ReplicaSet to 2 does not work because the port is already taken. This makes me believe I'm only supposed to have one pod per node but some information says otherwise. How can I run multiple replicas on the same node?

Question2: let's say I deploy 9 more nodes. Should all my 10 nodes be behind 1 Ingress Controller (and 1 Load Balancer) or should each node have its own Ingress Controller ?

Question3: if I have only one Ingress Controller, the Load Balancer does not really "balance" any load, its sole purpose is to expose my service to the Internet, is that normal?

Question4: what happens when the Ingress Controller is overloaded? Do I duplicate everything and then the Load Balancer distributes the requests on the 2 Controllers?

This and this is a good starting point, but still does not answer my questions directly.