Always good to have a plan, and nothing like honeybees to make changes to them as they see fit :-D
Yeah, 3 deeps is a lot of deeps IMO. I use all mediums myself but even when I used to brood in deeps it was just one Deep, topped w/ mediums and maybe a few shallows.
There have been and still are many beeks swearing by 'single story' hives though, with added honey supers of course. With all mediums I use 2 for brood, but the concept is the same. DEEPS ARE HEAVY (even 8 frame)!
I'd add a honey super right away (on top of that 'one' brood deep) as dandelions should blooming when your packages arrive and they will soon ignore nearly everything else you might give them.
As your using a 'foundationless' system and it sounds like you're low on empty drawn comb frames, stick in some frames with foundation, placed alternately (empty, foundation, empty) to be removed later. Just mark them ahead of time.
Here's a little trick to keep your honey comb clean with a foundationless system if you're producing cut comb honey (why else, right?). As the bees fill the top honey super you gave them when first hiving (their honey), place another empty (your honey) honey super "UNDER" it (above the brood deep), as it will cause fresh 'new' comb to be built very quick and traffic (beefeet prints) over it will be light. Once full (you gotta look), remove the whole super and put in another empty, in the same place, keeping a "nearly full" super always on top. You'll harvest clean comb honey from the middle one for the season this way.
I absolutely love the idea of storing NUCs in an unheated, dark garage/shed with that access outside. Gonna do that myself, yes sir.
Yeah, I'd just build up your packages and split/NUC them. Buy some queens until you know "what method" ( there's a few) you prefer as a hobby beek to raise your own. More and more beeks are raising their own queens these days, but the best is when several "likeminded" beekeepers from the same region can get together and share bee genetics by simply sharing queens. 8-)
You may say I'm a dreamer, but I'm not the only one.............. JL
LOCAL/REGIONAL BEES RULE