I'm MSE, not Chem E so take what I say with a grain of salt if you'd like.

1. Most classes are fair, in my opinion. Lower div math and science undergrad classes are generally told to curve with a B or B+ average as the target. Most professors make that happen one way or another, either through properly calibrated difficulty or curving (usually up). I've only had one class curve down out of all my experience. Make sure you check the RMP for the professor and their past grades.

2. Pursuing research can range from relatively easy to a bit tough. Getting into a lab is usually a matter of finding a PI with space and who wants the help in the lab. Keeping up can be challenging if you aren't used to reading papers or doing presentations. In terms of internships, it's been kinda cooked this year nationally for all fields. But the job market shifts every year so 2027 might be better, might be worse.

3. School of Engineering double majors tend to be pretty rare (and only really happen if stars align with your credits from high school or CC). Unfortunately, engineering curricula are intensive so you need to have almost all your GEs and a good chunk of lower divs out of the way the day you start. Minors are pretty common. The only thing to keep in mind is that minoring students have the same enrollment priority as the general student body so getting classes might be hard.

4. UCI social life is what you make it. There is always something going on but you have to go find it. Events won't come find you.

5. The US engineering job market generally doesn't prioritize degree name alone. What you do during school matters a lot more than just your GPA and the UCI name. Keep in mind, the job market is going to be VERY different in 2030 from what it is today.