Our Logan is a day short of ten weeks. We were eager to have a companion on our family hikes when we looked into huskies- how old does he have to be to start backpack training? Are there non-weighted "packs" for pups to get used to having something up there? Also does the five minute per month rule apply on all terrain or just cement?

I do not use back packs, however, I would refrain on buying one now or any time in the near future, reason being they grow fast. You also do not know what type of husky you will have, on males and this forum I have seen males go from 40 pounds up to almost 80 here. Impossible to know how big Logan will be. It will cost money in the end having one that fits at 4 months old may not fit at 5 months.

As far as the 5 minute rule, well, hard surfaces is the thing, cement, pavement. But, rock climbing, mountains, heavy terrain should be dealt like pavement. Gsd's have more issues with bones and joints over husky's, with me we stick to the 5 minute rule in general. Outside playing and running around, where they can stop and rest doesn't count. We like to trail walk, and it is 5 miles round trip, when Sofie got tired my husband would carry her, as she got a little bigger, and still do take our time. Obviously 5 miles will take longer than 35 minutes, which is the rule with her being 7 months old. So we limit this type of walk for about once every 2 weeks, and when she was younger one a month. The terrain is pretty flat, for the most part and it is all dirt, so no pavement walking. With Miya, we probably followed that rule and didn't know it, since she would stop and sit whenever she got tired. They will not show that they are hurt, so being mindful of how long and keeping it to grassy level areas are best.

Is it 5 minutes per month every day? or do we have to space them out? He loves walks and meeting people in the neighborhood.

No you can do this several times a day. Miya was the mouthy one, and her puppy boot camp that I did with her was, example 3 months old 15 minutes probably 8-12 times a day.

That's good news!

Alleriel (and if I may without being too nosy, what's the derivation of your name? Hebrew?)  generally it's per session.
If you take her on a walk first thing in the morning (ugh!) then it would be 10-15 minutes; ditto about a noon walk; ditto about an evening walk.  It's not that you don't want a tired pup, it's that you don't want a pup whose joints have been stressed.

Also, the 15 min per set does NOT include any free time where he can run and play if he has the option of stopping on his own.  We assume a pup in the back yard, for example, can run, chase birds, etc and then stop and relax when he's tired.

ETA: and I obviously have no idea what gender this pup is - it's a male al! (I think)

Oh he's all boy unfortunately our large yard has no fence, so we run him around on a long lead during the day.