This makes me very sad as I wanted to make a cute little pong game on my cute little 16x2

Could be done but with care redefining the 8 custom characters as needed.
I definitely think that this could be done.
The odd part will be is that there is a horizontal gap between the 2 lines
on most displays.
If you think about it, you only need a maximum of 6 custom characters.
2 for each "paddle" and 2 for the ball. (only 1 for the ball if the ball is 1 pixel)
example:
0 and 1 are for the left paddle.
1 and 2 for the right paddle
3 (and 4 if more than 1 pixel) for the ball.
All you have to do is "draw" the pixels you need in the custom character
data for the custom characters with the pixels you need for each "frame" update.
For the updates,
You won't have to do anything for the paddles other than load the new custom
characters, as the new custom chars
will "magically" update/change the paddle characters/pixels as needed as soon
as the new custom characters are loaded.
For the ball, just use cursor positioning and write a <space> to the old position to
erase the "pixels" (custom char). Then update the new character position(s)
with the new custom char(s) to draw the new "pixels".
Sounds like a fun little project
Would be interesting to play against the "Arduino" .
--- bill