No, you must meet income to sponsor both parents, or none. You can't pick just 1.We got selected in 2nd round for my wife's parents, however we just realized that we do not have sufficient income since I already submitted the sponsorship for my parents earlier, can we just sponsor only 1 parent instead of 2, we are only short of a few thousands for the first of the 3 years required for income, this is so sad!
All parents being sponsored in total (so 2 already + 2 new ones) would need to be added to family size, for both apps.