Individual panel sections have different heights, so it doesn't necessarily require a "custom" door. It's not uncommon to have a short door if there isn't space for a tall one. GF has a 16' wide door that's right around 6' high, as that's all that would fit below the header. It has the double track to allow a small radius bend at the top, and it's adjusted to sit really close to the door opening as far as height goes. Proportions look wacky, but she didn't want single doors.
OP's door size can be made to work, but using it for the Highlander is likely going to be a PITA. I keep a hot rod in a garage that's barely wider than the car, and I hate moving the car in & out even the once every couple of months I use it. At 76" before mirrors, I'm betting that the Highlander will require folding the mirrors every time going into that garage. With mirrors folded, that's 4" on each side for clearance if the mirrors tuck in to body width in the best case. Is there weatherstripping and trim around the garage doors that reduce it below 7' width? How attentive are you OP every time you go into the garage?