That 26F you linked is the same cell that Barkuti mentioned above at $2.21/cell. Cells from name brands will have the rated capacity - Panasonic, Sanyo, Samsung, LG. Only the “xFIRE” type cells lie about their capacity, and you will never see a spec/data sheet for one of those crappy cells.
Here is the best resource you could possibly imagine for good info and independent testing of batteries: http://www.lygte-info.dk/
I think 36V is low in the world of full-size ebikes. Maybe some “toys” are 12 or 24V, but most real ebikes are 36, 48 (overvolted to 52), 60 or even 72V. Higher voltage means less amp draw for the same power output, and hence less strain on batteries.
Will you plan to have a second charger at work? If so you could get away with a small battery pack and re-charge during the day. But I would rather just have the one charger at home and divert that $ towards a bigger battery pack.
You said your 4.8 mile commute can take 30-45 minutes - really? Is that actual moving time, or all-inclusive time including waiting at lights and such? Grab an app like Strava and clock your actual moving time, I bet it’s closer to 20 minutes. Also, do you want the e-bike to do nearly all the work, or do you plan to do much of the work and just use the motor to help get up / keep up with traffic at certain points, or tackle that one really nasty hill?
Using the 26F in 14S2P, (28 cells, $62batt cost, 52V, 5.2Ah, 270Wh) you could run a small 250W motor about an hour. But that will be fairly stressful on the 26F as it is not a high-drain cell by any means, and 250W is small by e-bike standards. But you would get about an hour runtime out of that battery/motor combo.
26F in 14S4P (56 cells, $124batt cost, 52V, 10.4Ah, 540Wh) would be more than sufficient, and more appropriate, I think. And still only $124 in batteries. And you could get about an hour out of a 500W motor, which is much more helpful.
Liitokala 26650s in 14S2P (28cells, $114 cost, 52V, 10Ah, 520Wh) would handle the drain better than the 26F14S2P and be slightly cheaper than the 26F 14S4P.