I have the experience that;
1) Working solution keeps surprisingly well,
2) Concentrates keep surprisingly poorly.
I know this may sound counterintuitive.
I think you won't have the problem of concentrates going bad as you have decanted them to smaller bottles, but still, I think you would have no problem with working solutions going bad either. Small kit manufacturers usually give shelf life of one month or so, but OTOH, they also give shelf life of 6 months for the concentrates and I have had the concentrates die before that, but never the unused working solution in 6 months!
So, if it is just a few months, mix the whole liter at a time and squeeze the bottles well. Store in a cool place (but not too cold) to further increase the life if necessary.
I use Fujihunt 5 liter kit and because of the hassle in mixing, and decanting the concentrates to better bottles, I decided to mix the whole kit at a time and keep the unused developer working solution in a fridge. No problems yet.