As far as your GPA goes, highly selective colleges don’t really care about how your HS calculates weighted GPA. They look at UW GPA, whether the “most rigorous schedule” box is checked by your GC, and for further context they look at the HS class report that comes along with every transcript giving details on how many kids take the more advanced classes as well as class grade and standardized test grade/score distributions.
All your arts ECs are great for a first semester HS sophomore. What will they be like, and how will your portfolios look compared to RISD applicants (you have to be separately acceptable to Brown and RISD, so you need to be at the top both in academics and arts) in 2+ years? No way to know at this point.
Even if they are and assuming you nail the academics over the next few years (at UPenn, for example, the average UW GPA is 3.9/4.0, 85% have a UW GPA of 3.75 or better, 96% were in the top tenth of their HS class, and the 75th percentile SAT is 1560) you are going to have a dilemma. If you pull down these stats, the legacy boost is real, but it only helps in the ED round. So, with numbers like that you’d probably have around a 30-40% or better shot ED at UPenn (and similar at Cornell) v no better than high single digits at the other schools RD. On the other hand, if your ED application is accepted, you’ll never find out if you would have been accepted at the other schools.