Good video and a nice Pike.
Bit of a pedant here: the engine at the rear end of the train is more properly called a Pusher. A Helper is cut in in front of the train's locomotive.
Yes - and any mid-train locos are also called "helpers", and you are not a pedant for mentioning it. Mid-train helpers existed in steam days, also.
Oh - almost forgot - great video, pushing, helping, whatever.
There is something of a half-true myth that 3RO is not a good venue for pushers, due to the typically truck-mounted couplers. They sometimes (not typically) tend to skew, then derail, when pushed, as we 3RO'ers know from switching. But - it does not usually happen and obviously, from this video, 3RO pushing is quite possible. Right equipment, right operators - yes, it works.