Christmas SEA MDW RDU "?"s

Time for the Christmas pilgrimage to grandma's house.
Flying Southwest, 1st time thru MDW (Midway). Here's the outbound
itinerary:

Monday 20 Dec SW fl 202 to MDW (Chicago) dep 7:15 am, arr 1:10 pm

SW fl 2390 to RDU (Raleigh-Durham) dep 4 pm arr 6:45 pm


Couple of "?"s for the seasoned vets, naturally I'll call SW too, but just
in case you folks know as much/mo

How much time to allow @ SEA (Seatac). 2 hrs? We need to make sure we get
a full row (spouse is full figured + partially disabled, we always buy three
seats for the two of us) - will we need to get there super early to get the
1st round boarding, or will SW let us on before others due to spouses
condition & our "extra seat" pax? (walks with a cane, but slowly & only
short distances)

Anyone know if FL 2390 is sub-737 equipment? We've had trouble with some of
the commuter jets (seat-width wise).

Should we expect the same 1.5 hr - 2 hr delays (usually ground holds)
departing MDW as we have always had when transiting O'Hare?

THX to all and Merry Christmas!