I still think I'm going to get this kit, but I have another concern. Any insight is appreciated!

I'm thinking about downsizing from having 3 bikes to having 2 bikes, partially because I'm going to be living in a more compact home (a condo), with less space for bike storage. I currently have: a vintage road bike (27" wheels), a commuter-type bike (26" wheels, with IGH), and a folding Brompton. What I'm thinking about doing is replacing the two full-size bikes with something in-between the two. The overwhelming majority of my riding is commuting, but I do the occasional recreational or fitness ride too. This one bike neeeds to be high-quality, relatively fast, and not heavy (before the electric kit is installed). I'm not sure whether I want drop bars or flat bars yet but I'm leaning towards 700c wheels. So far, the bike I like most for this, based on online research, is the Trek 9th District.
I like the relative simplicity of the 1x9 setup and I'd rather have a derailliuer than another IGH.

My concern is: can I set the bike up to be relatively easy to convert between having and not having the eZee kit installed, so I can remove (at least) the front wheel w/hub (I'm going to have a spare wheel anyway) and the battery? I reckon those two components are probably 90-95% of the weight of the kit. The rest I can probably leave on. I need the electric installation to be weatherproof, and I'm plenty capable of redoing the wiring/connectors. For example, it looks like there are multiple connectors for the hub; I might want to modify this to get down to one connector. I want to be able to switch between having the motorized hub wheel and battery and having a "normal" wheel and no battery in no more than a few minutes. This way, I could have "one bike to rule them all". A full schematic (I haven't been able to find one) would help. What do you think?

This is a difficult decision, as I haven't actually used the eZee kit yet.