For Computer Science, it’s important to note that UBC has a secondary admissions process. Your daughter would not apply directly to Computer Science, but instead would apply and enroll in either Science, Arts, or Commerce, and then apply for CS once she is already a student at UBC. Here’s some information: High School Students | Computer Science at UBC
Regarding merit scholarships for international students from the US, when we visited UBC and spoke with an admissions officer, she told us that grades are the most important factor in awarding merit scholarships. She said that merit was typically awarded only for “straight A students.” My son (US citizen) applied and was admitted for Applied Science. He wasn’t quite a straight A student (he had one B on his transcript), but he did receive a small merit award when he was admitted. Merit awards can be quite substantial for some students. It’s worth a try if you like UBC.
For the personal profile, my son thought it wasn’t very different from essays for a US college application.
I get the impression that the secondary admissions process for CS at UBC can be quite competitive, so if your daughter is only interested in studying CS and wouldn’t be happy with any of the other programs, this may be an issue. Secondary admission to the program is based primarily on the grades that she would earn as a UBC student, so there’s no way to guarantee admission to CS before she would start there. There is some information at the bottom of this page under “Admission to CPSC Specializations for Current UBC (non-CPSC) Students”: Degree Programs & Options | Computer Science at UBC
I would suggest talking to UBC Admissions with all of your questions, including questions about the secondary admissions process for CS. They were very helpful when my son was considering UBC.