I know my previous answers didn't help you, I hope to help you now. :)
- Yo lo preparo.
- Yo los compro.
- Dolores las hace.
- Juan los trae
- Yo los invito.
To replace the accompanying noun, write a direct object. They can be replaced if it is masculine it is "lo" (singular) or "los" (plural) and if it is feminine it is "la" (singular) or "las" (plural).
Note: I think that section 2 and section 3 must remove the verbal periphrasis; stay with the conjugated verb.
MissSpanish