Considering the point 4, I will ask you why use Kubernete and why not use a full managed cluster as fargate (on aws)? From my experience, I've deployed a rich functionnal site based on multi java containercontainers, all this has been hosted on fargate without any issue (and in production context) and put a load balancer in front of that to secure and handle the cluster scaling policy.
If your final goal is to run java container, AWS and Azure provide a full managed service to host containers (which feature like scaling / service catalog etc...).
This solution befenefits it's to avoid all kubenetes admin / setting tasks, and this tasks could be really penfull in some project. But in other hand, this service have a cost, so all this must be considered to made the good feet for your use case (but keep in mind that kubernetes it's not the only solution to host java container in the cloud).