Your plan should work, just don't leave them in the garage if they are at risk of freezing. If freezing isn't a problem potting up should be ok, just don't use overly damp potting soil or give them additional water until it warms and they go outside and begin to grow. Personally I would just wait. I can't think of any advantage (plant-wise) to potting them up early.

I've had them be hit or miss in zone 5 depending on how protected they were and the winter. I for sure would lift them in a zone 3. I have put in glads 3-4 weeks before the last frost during a mild spring and they have been fine. I wouldn't try pushing it further back than that unless they were in a pot I could bring inside if it got too frozen for too long. I have no idea if Calgary is getting a mild spring right now, but I think it might still be too many weeks before you last frost date to risk them.

Haha, yes, exactly - that's when I cut them to put in a vase! But then again I always grew mine specifically to cut. Illini that's great that you haven't really had this problem! I always have a few that face-plant, lol. Actually, I grew glads for a few years when I was selling bouquets at market. I would buy new bulbs as they are not winter-hardy here and I didn't want to dig them up. When I stopped selling bouquets, I no longer bought corms. That was over ten years ago and I still have a handful that pop up each year. It's always nice to see them return, but they still occasionally face-plant on me! :) Dee

To safely store them, begin by ensuring that the plants' foliage has naturally died back, which is essential for the corms to store energy for the next blooming season. Once the leaves are yellow and wilted, carefully dig around each plant using a spade or fork to avoid damaging the corms. Gently lift them from the soil and shake off any loose dirt, using a soft brush for any remaining soil without harming the corms. The corms should then be cured in a dry, well-ventilated area away from direct sunlight for about a week to harden their outer skins, which helps prevent rot during storage. After curing, clean the corms again, remove the old, dried-up corms from the base, and inspect each one, discarding any that are damaged or show signs of disease. For storage, place the corms in a cool, dry place with temperatures ranging between 35-45°F (1.6-7.2°C) and good air circulation. Mesh bags, old pantyhose, or cardboard boxes filled with dry peat moss, vermiculite, or sawdust are ideal for storing the corms as they prevent moisture accumulation and fungal growth.