@Tedbow00, it looks really good. Great news that the roots look healthy! Since the roots are ok and you did no cutting on them, you can repot it right away in well draining soil like I described before. Water it in once it's potted, but then don't water it again until it's either completely dry. At this point while it has no active growth, over watering will certainly be a death sentence.
Once you see new growth again, before watering, feel the caudex. If it feels spongy, and the soil is kinda dry, water it. If the caudex feels very taught or hard, it's not ready for water yet. Right now it will probably feel spongy for a little while since you just pruned and repotted it - may take several weeks or more to tighten back up, so don't worry and just be careful and limit the water. I received several new ones this spring. Most of them tightened up after about a week or so, but one stayed spongy for probably over a month. I just knew I was going to lose it, but I just stayed careful with watering that one - only when very dry - and eventually it perked up and took off.
You can prune any time it's actively growing. Pruning while dormant can be done, but I wouldn't do it. It invites greater opportunity for disease as well as may delay blooming. I would prune in summer after the spring flush of blooms. You won't need to worry about pruning for a while, though. Since you had to cut back so drastically, you probably need to let it grow for at least a year before really starting to work on branch structure. The up side is that since you had to prune so drastically, you should get several new branches from the neck of the caudex and can be more active in achieving whatever shape you prefer for it.
You can leave it out until we really start getting cold at night (well, cold for us, that is) - like maybe below 50F. It will survive lower than that, but any soil moisture will intensify potential for rot at that point. You can move it back out once lows are consistently back in the 60s, but again just beware of early spring rains. Once you see active growth, you can worry less about rain unless we are having the weird daily downpours that don't allow it time to dry a little.
I think the easiest way to fertilize is to use the time release fertilizer like osmocote. You can fertilize up thru August, maybe even September, but I wouldn't after that.
At this point I would leave it outside in a semi-shady spot since we are still pretty hot right now. Once you see a few buds popping out on the stem, move it to maybe 50% or more sun. Ultimately, it can be placed in nearly full sun once you have it back to good health.