Essentially, I need only one theme (if I can find or create it). It would be really helpful, though, if you’d offer some alternative solution idea.

Would it make sense to use Wordpress as a front and dokuwiki (via API?) in background? We will need wiki anyway for other purposes.

I am open to suggestions.

It all depends on local conditions.

1. The “last mile” loop will be different in Europe, in Africa, North America or Australia. It shapes your need for speed and range, as well as required safety (how long will it take to get assistance in case of need).
2. In rural applications you rarely need strictly personal transport. On average it is a 2-5 people and some cargo, with occasional trailer.
3. Serviceability is an important factor.

For Eastern Europe, where I live, I would recommend a slow (~45km/h) pickup (2 + 1000kg) - the one pictured below. For extended range you can add a PV canopy and even a small gas-powered genset for emergencies.

https://www.melex-ev.com/cargo/