Rashford is actually more comparable to Iheanacho. Both coming through academy and scoring some important goals. Some glimpses of quality, but still a lot of work in front of them. Martial and Sane are also similar in a way, both playing wide, and arguably even more talented. Martial seems to have more goals in him, but Sane looks more complete player.
Gabriel Jesus is something different. The fact he already led his team to the title, and leads the line for Brasil should tell something. In addition to natural talent, he has some exceptional smarts, guile and tenacity to his game. Although playing completely different positions, he reminds me of Modric when he came to Spurs. Looking deceptively light, but very strong on the ball, industrious, quick and intelligent.
He is also the first player in a while that reminds me of Romario. Maybe not as superb on the ball, but with more workrate and intensity to his game.