re: It has an elongated orbit. Passing it close by from a circular LEO...
"...when it is at its perigee will still result in a large difference in velocity between the two bodies. Not the full 18k mph, of course."
If escape velocity from LEO is around 3 km/sec, then it's somewhere less than 1/2 of this- say around 1 km/sec or 2000 mph.
You would need to match it's orbit to dock with it- otherwise it would be similar to trying to catch a bullet.
Catching a bullet would be easier because a bullet could withstand the gees of decelerating more easily than this somewhat fragile satellite [and bullets don't weight 4 lbs].