just wanted to offer a follow up.
1. we are buying two new control arms from rockauto. cheaper to buy two from rockauto and pay for shipping to Canada than to buy even just 1 locally.
2. euro-bred is kind enough to sell us the bolts we need.
3. we are going on vacation for a week and a half and won't easily be able to replace the control arms before leaving so we needed to either borrow a car or come up with a temporary fix for our car. today we put together this fix in the photo below. keep in mind that the seized bolt is still in place and hasn't budged whatsoever. as you can see in the photo, we have sandwiched the bolt between two metal plates which are bolted together with 2 bolts, nuts, and washers. that seized bolt couldn't move even if it wanted to! (it probably wouldn't move anyway, since it is SEIZED! but we wanted to be just extra cautious)