is there a way to add an analog station on a spirit 2448.

Yes. You need a ConnecTR. I haven't seen one in about 5 or 6 years. I have a PDF owners manual if you would want one. PM me if you do.

I think the immediate answer is no due to availability , but they did make a unit called a Connect t/r for single line devices.
They were rare 15 years ago ,maybe someone here has one collecting dust. or confirm it will will work for a single line phone.

typing while you posted

Perhaps this might be a great time for an upgrade???

on a spirit line pack there is a line aux that goes to the first line on that pack for to use on an analog device

I think I have 2 Connect t/R if you are looking for any.