I understand that these are officers,but what use or how does one employ them. If you cannot what is their function please

Would someone kindly assist as I am returning after quite a long break

You can employ them for 10 credits by going here

For a month they gather units of cocaine that you can sell for profit. They also help you by giving you unit ranks (when you have the XP) without having to tip, and help keep you out of jail.

After a month you will get a personal saying they will retire in 24hrs, which you may either shoot before the time is up or allow to expire.

Hope this helps. :)

Quick question about this... What is the use of seeing them in the "Members online in the past few minutes?

I'd assume it's a byproduct of the mechanic which activates them to be available for pickpocketing (as most characters are visible when active, including admin/helpdesk accounts and even webspider), but that's a guess and very much open to correction there.