M&T does not admit by major. Many M&T and Viper (the other Engineering Dual degree) change their majors. ChemE and the very similar Materials Science E are popular at Penn especially in the dual programs, and the Chemistry department is known for being very strong with a lot of cross-research of professors connecting Chemistry to the different Engineering fields and to innovation endeavors. Penn is quite interdisciplinary and the major you select will not likely have any effect on admission to M&T. I do think your course rigor is exactly what the dual programs seem to select, but it is a hard admit for everyone. ED makes it slightly easier than RD. Make sure you understand WHY M&T and can articulate that well.