How hard is it to internal-transfer to College of Engineering from, say, a physics or econ major?

My student was admitted to TAMU but the college is undetermined at this point, as he is still in Engineering review. From the worst point of view, lets say that he starts his college at TAMU with a physic or econ major.

how hard will it be for him to transfer to College of Engineering (1. EE major 2. ME major) after the first year?

What is the criteria? I know you are required to take some fundamental engineering courses in your freshman year. Can an econ major student take those courses without any restriction? What would be a solid GPA for internal transfer? 3.5? 3.8?

https://engineering.tamu.edu/mechanical/prospective-students/admission-guidelines

Link above provides a list of courses a student should take who wants to internal transfer into ME. It’s sounds possible.

I know a friend who is a physics major who was able to take all the same classes a freshman engineer could, including ENGR 111. Only difference was that instead of taking MATH 151(Calculus for Engineering Majors), he had to take MATH 171(Analytic Geometry and Calculus for Science Majors), but they count for the same credit. Also, for both Electrical and Mechanical engineering, the average GPA for admitted transfers was greater than 3.5, as shown from this site:
https://tap.tamu.edu/main/changeOfMajor.pdf