Surprised that you didn't post the video you created:
Many outstanding elements to the Sampras serve that make it worthwhile studying. However, the extreme lag of his racket (head) compared to the toss is something that most players would have a difficult time emulating. He has a fairly high toss as well that might be a bit challenging for many. I used Sampras as my model in the early/mid 90s but need to modify it somewhat for less lag and a lower toss height. I find the toss height that Federer employs is more to my liking.
The similarity between Ram's serve and Sampras' serve is uncanny. It is certainly intentional. However, Rajeev's implementation is somewhat flawed IMO. Note how far to the left that Rajeev lands and falls on his follow-thru. In the vid above, Rajeev is serving to the ad (right) court whereas Pete is serving to the deuce (left) court -- yet Rajeev falls off to the left more than Pete does.
First notice the right leg. Ram's right leg kicks off to the right whereas Sampras' right leg does not -- it kicks back toward the camera instead. Now look at the left foot. Pete's left foot lands in the direction of his serve. Ram's foot is turned quite a bit to the left when he lands. Theses actions of the right leg and the left foot is why Ram falls off to the left quite a bit -- rather than in the direction of his serve. He seems to be over-rotating his body a bit too much.
Pete is driving up and forward more. This might provide for a better energy/power transfer to the arm/racket for his kinetic chain. It also makes it easier for him to follow his serve to the net if he desires. Rajeev is moving in the wrong direction to follow his serve to the net. I suspect that he doesn't follow his serve very often in singles anyway but it could be a liability for doubles.
Pete's gets more air as well -- his upward drive is more explosive. Rajeev may be losing some of his upward drive by over-rotating -- too much energy going to the left rather than going upward.