I have room (and personal ability) to expand by one hive to five. Last year was my first year to overwinter hives - so, IMHO, I now claim beekeeper status. Did not feel I could do that until I overwintered successfully.
So, current status is four hives, with one in a single deep. Resolution is to solidify beekeeper status by babying these bees through this winter and splitting to five hives this Spring.
Congratulations on your success!
I am glad you didn't give up.
Unfortunately, colony loss in the winter is a challenge for many new beekeepers. As you have probably figured out, the secret is to determine what went wrong and then, in year's to come, ensure that it doesn't happen again.