My situation:
Flying BOI-DEN, 2.5 hr. layover, then DEN-SAT with my wife in Oct. This flt is the last one of the day ex-BOI, arriving SAT at 10:45pm.

-Would it make sense to buy EBCI just for me and then I save a seat for her (probably a window/middle or aisle/middle combo)?

-If I don't buy EBCI and then do OLCI at T-24 (easy for me to do) will both flights have a similar priority, say high A or low B?