I need to fit DS, DD, and my cousin in the backseat of my 2003 Mazda protege. DS is 46# and 44" tall, DD is between 18-20# and I don't know how tall but wearing 18 months clothing, and my cousin is 11 and a few inches short than me (I'm 5'9"). I have a touriva, comfort sport, nautilus, turbo booster, and a true fit. Do you think I can fit the 3 back there. If not my cousin can ride in the front but I would prefer the back.