Hey, valterri already made a remake of SMW but i you are doing one for 1.4 so i guess its fine.
[question, does anyone know how to like make blocks with sizable physics (stand on top, when you jump from the bottom you get to the top)
Yes, you can edit the block properties by right clicking them from the tool box and then doing this.

And do the same for the npc collision as well.
change the textbox sprites
You can't do that since this is a hardcoded gfx and 38A doesn't allow us to modify them, the only solution is to make your own textbox system, this one is a good one but is a bit complicated to use:
viewtopic.php?t=18502
and make berries (currently using redcoins as a substitute)]
How do berries work in SMW? It shouldn't be hard to implement them.