Droplet resize: CPU/RAM-only vs disk-inclusive path for a low-traffic workload

Goal

I want to reduce monthly cost for a low-traffic workload running on an over-provisioned DigitalOcean Droplet by resizing it to a smaller plan. The Droplet is billed hourly with a monthly cap, so moving to a smaller plan should lower the rate, but I need to pick the right resize path before powering off.

Uncertainty

DigitalOcean documents two resize options: a CPU/RAM-only resize that keeps the existing disk and can be reversed later, and a disk-inclusive resize that is permanent because disk size cannot be reduced afterward. My data fits within the smaller plan's disk, so both paths appear open, but I am unsure which trade-offs matter for a workload that may grow again. I also understand that after a disk-inclusive resize the filesystem may need manual expansion before the new space is usable, and that backups are billed proportionally to the Droplet cost while snapshots are billed per GB, so right-sizing may not reduce all line items.

Questions

1. For a low-traffic workload that might need to scale back up, is the reversible CPU/RAM-only resize the safer default, or are there cases where the disk-inclusive resize is still preferable?

2. If a Droplet previously had its disk enlarged, can it still move to a smaller compute plan while retaining the larger disk, and how is that billed?

3. Which of these behaviors should I re-verify against the current docs before resizing, given that plan names, prices, and resize rules change?