Winterize before doing plumbing repair?

Since summer is over (sob) I will be doing some repair work on a soft spot on the bathroom floor. I suspect I have a leaky toilet so will be removing this and pulling back the lino to inspect the damage. Depending on the amount of work and my available time, there is a real possibility of not completing by the time cold weather hits (mid-Oct where I live). So I was thinking it be best to get the antifreeze into the lines first as I will not be able to do this later if the new toilet is not reattached by then. I would have some pink, sticky stuff to deal with during the toilet removal but at least the remaining lines will be safe from freezing, even if some of the antifreeze 'escapes' when I unattach the toilet intake.

Am I correct in assuming that the lines don't need to be full of antifreeze as long as there is no water present (i.e. the antifreeze removes the water when I pump it through the lines)?

I will probably have lots more questions once I start this project but for now, any advice on the winterizing idea is appreciated.

Howie