Clem,
Georeg is half right:
Do I have to have my locomotives on the track to edit remote address?
Yes, you must.
If not, the DCS Remote will display an error message, or two.
Do I have to have locomotive on track to delete address or delete lash up ?
No, you do not.
Be aware that if you delete an engine that's a member of a lashup, DCS will also delete the lashup.
This and a whole lot more is all in MTH’s “The DCS O Gauge Companion 2nd Edition", available for purchase as an eBook or a printed book at MTH's web store!