Does anyone know what these are?

I would love to know what the names of these three plants are. All were cuttings from a parent plant. Through trial and error I found that plants 2 and 3 don't do well in full sunlight. Any additional information would be greatly appreciated.

 

First is an Epiphyllum.

 

Thanks so much for you help.

 

1. Eiphyllum oxypetalum
2. Cissus quadrangularis
(3. Hm... maybe Huernia schneiderina...)

 

Thanks for your help. I love plants of all kinds but unless I know what they are I don't know how best to care for them.