Do you think the vacuum sealing is important for long term soap storing? It never really occurred to me but I suppose it couldn't hurt. I've a lot of soap and some of it doesn't really get used very often.
I just tend to screw the lid on tight then put the pucks in those plastic storage boxes and then just close the lid. Maybe it'd be worth sealing up some of the backups or ones I'm not using much.. and then putting it in the storage boxes.. or maybe that's just overkill.
I now have a dedicated "soap room" where I store them all along with my razors and blades etc. I keep it cool in there and never put the heat on in that room to keep the soaps cool.
IMHO, you are doing most of the right things in keeping the soap sealed in an airtight container in a cool and dark place.
Vacuum sealing is a step beyond all that. It wouldn't hurt anything if you wanted to preserve as much of the scent as possible.