It depends entirely on the host. Some hosts would never pick either skater, some would. For instance, Japan would have no problem picking either of them because neither is competitive against Japanese skaters. But Courtney has medaled in Russia, so Russia would be unlikely to pick her again.
I doubt France would pick either Angela or Courtney, as both have SBs in the 80s; the French ladies have SBs in the low 70s (perhaps that's why Algotsson, with an SB in the 60s was invited). The rest of the field are heavy hitters with SBs of 192-238.
Also, distance is a factor, particularly when there is a last-minute vacancy. Canada might pick one of Courtney or Angela if there was a withdrawal close to two weeks of the start date of SC. After all, USFS did pick Chartrand and Reynolds for their SA vacancies, and the time wasn't close.
BTW, Angela didn't have a GP slot last year because in the 2016-2017 season she was injured and didn't compete in any GP, Challenger or ISU Championship events and so wasn't on the SB list (B events don't get on the list) and therefore not on the substitute list as well. Last season, because she was recovering from injury, she wasn't put forward by USFS for initial GP selection in the 2017-2018 season, but was given Challenger assignments. Angela did well enough at those events to get at least one GP invitation this season and is on the substitute list.