2 pulley chain tensioner and you can give it a try.. they're like a short cage RD
make the low gear within the range acceptable for the hub , big ring higher than that will be fine..
I've only used the big reduction gear 2 speed crank on my 3 speed.
It does not use an internal gear change, just changes the application..
the gears themselves never shift, only the pawls ..
(My Brompton, with a mountain drive crank.. ) 54: 15
Rohloff * gives you a minimum but higher gears are said to me fine ..
so the hub in my 20" wheel with a 53t chainring is better by their suggestions,
than the same hub in a 26" wheel with a 38t chainring.
* I have the manual for that, not for the Nexus, but you can find the one for your hub, online ...
How easy is it to replace a Nexus 7 for a Nexus/Alfine 8?
Order a pre built wheel from your favorite bike shop, through their wholesaler is simplest..
maybe go for their 11 speed and that will be wide enough a range?
....