1. They always leave some "margin" for curtain movement up to T-72. That's why you could only preassign as far forwards as row 10 which probably means the estimated curtain position would be around rows 6 or 7. At T-72 they firm up on the curtain position and release all the ET seats to those who can preassign. (If they then get a lot of last minute CE reservations they might move it back again - beware)

2. How wide is Jimbob jnr? If he/she is very small, he/she might even fit in the space that was 6B (something like 20cm wide IIRC) (other than for takeoff/landing etc) with you and Mrs in 6A and 6C.