There is answer to second question, first question is too easy. You must make one new parametre, as here
pygame.draw.rect(surface, (R, G, B), (x, y, width, height), thickness, newParametre) #see the last parametre
Here you must write number from 0 to 1/2 of max(width, height) (you can write bigger numbers, but they will have effect as I wrote).
Example:
