>>1174608700c rolls faster and rolls over potholes. Rigid 90s mtb are great but they are going to be slower than a 700c bike. The nimbleness advantage is not relevant.
The big determining factor is if you're a tall guy you probably more-so want the larger wheel size and if you're a manlet 26 might be better. Both are fine for either though.
>car substituteIt might be worth going custom build, or just getting a custom front wheel, to get dynamo lighting. You don't need extremely wide clearance unless you want something really comfortable, or something really capable for offroading, 32 or 35 + fenders is fine, even 28 maybe. I'd want a front rack with a basket & a steel frame + steel fork.
>>1174631Lowrider racks for panniers & full size front racks for panniers & platform (pic related) will both normally mount there. It's just the smaller front racks that are full legs but platform only and not designed for panniers that won't.
