LogTen Pro allows you to specify whether you prefer to display people using their name or their ID. This works in the same way as setting a preferred display type for Aircraft and Airports. You can always enter and find the person in the field using either one! So when you want to enter someone, simply type their name OR their ID in the name field and it will autocomplete the entry for you. In preferences you can change it to always show the one you prefer and that’s what you’ll see, both in the logbook tab and in reports.
On iOS go to More > Settings > Display Options > Person
On Mac go to Preferences > General > Preferred Person ID
Also note the handy button to swap the PIC and SIC. This is especially useful if you often fly with the same person but switch rolls. You can set defaults so you’re always added as the PIC or SIC, then just use the button to switch as needed.