Tribal Creatures?
Bitterblossom will be a 3/3.
Opalescence says to make non-aura enchantments into creatures, and that they're still enchantments. Since Opalescence says that they're still an enchantment, it means that will retain all of its previous supertypes, types, and subtypes. After Opalescence animates the Bitterblossom, the Bitterblossom will be a Tribal Enchantment Creature - Faerie. Since it is a creature with the relevant subtype, it will get the bonus from the Door, so in this case, Bitterblossom would get +1/+1 from the Door, making it a 3/3.
205.1b Some effects change an object's card type, supertype, or subtype but specify that the object retains a prior card type, supertype, or subtype. In such cases, all the object's prior card types, supertypes, and subtypes are retained. This rule applies to effects that use the phrase “in addition to its types” or that state that something is "still a .“ Some effects state that an object becomes an ”artifact creature"; these effects also allow the object to retain all of its prior card types and subtypes.