The roots will follow the medium to the water source. How wet or dry you keep the reservoir will determine whether those roots air prune themselves, but they will populate that footer assuming their is some substrate for the roots to hold on to (like soil, perlite, etc).Oh and I believe we can see something interesting in the last pic. It is the only container where the roots don‘t grow out of the bottom holes. But if you look at the bottom of the wicking foot you can see one root growing straight out of the left and another one poking out in middle at the very bottom. Looking at the root direction at the bottom of the container, it even seems that the roots grew towards the wicking foot.(@Azimuth do you know why this happened? Ever noticed something like this?) It is the Kosher Choco Kush 2, the tallest.
That's a pretty tall soil footer you have there and I'd be curious if you get much if any wicking action up to the main container.
That's actually something I want to test in coming grows, specifically whether or not a non-wicking footer might even help an organic SIP by making water continuously available to the roots without impacting the moisture content of the soil.
Might be the best of both worlds; plenty of water for the plant while being able to protect the soil from being over-wet and thereby well oxygenated for the mixrobes.
but after all it it is just my try to copy of what you guys already have achieved and luckily shared. Was sold to trying a sip since last summer when I tried the concept with a basil plant.
Hope all your gardens are doing well 
I hate mondays even if i'm on vacation...it is like mondays are the official downers for this world. 
