I was thinking these were both Cotyledon orbiculata but the first one has flowers that are not consistent with a Cotyledon orbiculata.
1: the smaller plant with yellow flowers is a Crassula of some kind, maybe C. dubia or a near relative.
2: I'll get back to you as there is more than one small shrubby green species - I'll have to hit the books!
Cotyledon species can be quite variable and can exist in many local forms C. orbiculata in particular can have both white mealy forms and plain green ones. Can you take a picture with a ruler in it as size can be deceptive with these