Finishing possibilities for my first cider

Hey there. I've got my first 5 gallon batch in primary right now and it's bubbling like a Kennedy's car at Chappaquiddick. Started with a 50/50 mix of unfiltered cider and filtered AJ, then added brown sugar and molasses (about 1 lb total.)

When primary is done, I'd like to try a variety of finishes to see what works out the best, so here's what I've come up with.

1/2 gallon cold crash in growler, age for a while
1/2 gallon cold crash in growler, backsweeten, age for a while
1/2 gallon secondary ferment in growler with stopper and airlock (do I need to add anything for this?)
1 gallon bottle and age
1 gallon sweeten for carbonation, bottle and age

That gets me to 3.5 gallons. I figure 1/2 gallon is also going to be consumed in the first week or so as I want to try it out on bottling day and shortly thereafter.

What should I do with the last gallon? Any brilliant ideas?

If you backsweeten without stopping the yeast, your sweetener will just ferment into more alcohol, unless it's an artificial sweetener like Splenda, etc. So you'd want to use campden tablets and potassium sorbate to stop the yeast prior to backsweetening. However, then you've got the problem of how to carb it, b/c you've got to have yeast or a keg system to carb!

You could spice it for the holidays or add a little of your favorite concentrated juice...

Pepper. Jalepeno maybe or that unbelievably hot one... Maybe a small chunk, it's only a gallon.

Good ideas, thank you.