Can the FAA CPL 2-hour cross country flight requirement include stops? One of the requirements for an FAA commercial certificate is:

§61.129: (3) 20 hours of training on the areas of operation listed in §61.127(b)(1) of this part that includes at least—
...
(iii) One 2-hour cross country flight in a single engine airplane in daytime conditions that consists of a total straight-line distance of more than 100 nautical miles from the original point of departure;

Since it just says 100 nautical miles from the original point of departure, would a flight that was 268 NM and 2h 29m, but included a stop halfway count for this requirement?
Also, does the &quot;20 hours of training&quot; mean that the 2-hour/100 NM flight needs to be with an instructor?
Affirmative.  That flight will have to be part of the dual training time required for the airman certificate.

And, yes, you can do a stopover during the flight; the experience requirement does not prohibit it.