Please note the latest common data set (CDS) I could find on the BU and the WPI websites:
76.78% of WPI students have GPAs > 3.75 with AVG GPA of 3.86
35% of BU students have GPAs > 3.75 w AVG GPA of 3.62
BU accepts only 29% of their applicants and WPI accepts 49% of their applicants. Perhaps these numbers are being used incorrectly to judge competitiveness for admission and for FA.
Historically, STEM focused schools have long attracted a discerning pool of math, science and engineering applicants. This phenomenon is called “self-selection.” When weighing your options, you will have a better grasp of the competition if you look at the matriculating students in the latest matriculating class. Because of the self-selection process, University acceptance rates do not reflect the caliber of your competition.
WPI is not a backup for BU. If you prefer BU, that is where you should go. Go where you are most comfortable with your classmates, environment and program of study. Your grades and test scores are respectable and you should be very proud of them.
If FA is a problem you might look into the cooperative education programs. Both schools also have these programs. It takes five years to complete the programs. A good co-op match helps financially and academically.
If the CC route is your solution, contact the school of your choice and find out where the university has agreements for transfer.