Admissions at universities in the US will have some staff who are familiar with the grading scales used in Hong Kong. You will be compared with other students who are studying in the same system. Most of us here on CC are not familiar with the grading scales in Hong Kong which might reduce the value of any advice we can give, but the universities will have staff who are familiar with Hong Kong.
From what little I know, “straight 2s” might be average, but is not any better than average in your system. My understanding is that this will not put you in the top 10% of your high school, nor even in the top 20%. Is this correct?
If there is one single kid in your entire high school, or even in all of Hong Hong, who is able to get 4’s in most of his or her grades, then that is the kid who is likely to get accepted to Princeton, MIT, Harvard, Stanford, Cornell, or Yale.
The list of schools that you are applying to have somewhat complex applications, which require essays. They have application fees. It is going to take a lot of work to apply to this many schools in the US. The application fees will add up. If you are not in the top 20% of your high school, then frankly to me this looks like you are wasting the effort, and are likely to end up in university in Hong Kong. Of course this is probably a good outcome.
Out of the 16 schools on your list, I would cut the list to perhaps 2 or 3 or maybe 4 schools and forget the rest of them.
If you ever get to the point of applying to graduate schools, such as for a master’s degree (which is possible but usually not needed for engineering), then your high school results will not matter, your grades in university will matter (but for now this is in the future), and the top schools in the US will still be there.