One other package of possibilities:

1. Red & Howard are brothers, either twins separated at birth or brothers from different mothers.
2. The person with the ventilator is none other than Howard's real twin brother - main problem TV-wise is introducing an invisible villain at the near-conclusion of the 8 part series.
3. Scottie could also be a 'twin' - the real Scottie Hargraves could still be in captivity