Is Daemon blocks remaining accurate when using --prune-blockchain?
Yes. The amount of blocks you must sync, verify and scan is the same regardless if pruning or not.
Pruning just affects how much data is stored.
The number of blocks remaining linearly decreases over time, but perhaps we are still skipping over some blocks aka pruning?
Per above. We are ...
It seems as if it is possible to essentially send the funds "to myself" via transaction from non-hardware wallet account to my hardware wallet account. Am I correct in utilizing a transaction in this way to secure the funds on my hardware?
"Busy" means one of two things:
the daemon has not finished syncing the blockchain
the daemon has not found at least one other peer
Run "status" in monerod, and it'll tell you about both these things:
The X/Y numbers at the start of the line tells you the height it's reached vs the height it thinks the network reached. It'll download ...