Good input here. Also would add that in addition to strong grades and test scores, many colleges may make merit scholarship decisions based in part on the nature of ECs. Some seemed particularly prone to offer merit for high levels of civic engagement or meaningful, ongoing community service. Others may favor different activities. Not suggesting resume padding here, just noting that pursuits done sincerely, with depth, that relate to who the student is, may play into the decisions. For our non-ED kid, some schools were very responsive to 4 years of increasing levels of responsibility and visibility in community service. These colleges rewarded that consistency (in spite of a bit of unevenness elsewhere in the transcript) and also had no application required merit aid. Scoping out what schools consider as part of these decisions may help with matches for your twins.
Best with this. I have seen far more problems when people aren’t realistic about costs, than when they are direct with their kids.