Sure, one person can, but doesn't make sense.
Presuming both are paying into the pool and using internet, fixed costs are $32/day for Crew Incentive and $15/day for MedallionNet (assuming eligible for 50% discount and to present best case scenario). That is $47. Now add one Plus Beverage Package for $77 and we are at $124/day total - roughly. Now, surely the other cabinmate is going to get some occasional drinks of one sort or another, which only pushes the $124 total higher.
Two PLUS Fare upgrades are $120.