Am I still charged for the Linode if its powered down?

There is still a charge.

Reference: How Linode Billing Works

If you power down Linode, you will still be charged for the resources
that were allocated towards your Linode. The resources remain reserved
for use so charges will occur. The only way to stop being charged you
need to remove a service from your account.

Make a backup to your computer and delete the linodes. You’ll lose the IPs tho.