Hi, It has to do more with the subject to which you're referring that to the meaning itself. Below are my 2 cents: Vivo: is more related to a state of being or to refer the place you live. Ex: - Mi gato sigue vivo aún despues que lo atacó un rottweiler. - Desde hace un año vivo en los Alpes Nevados. Viviente: mostly used as an adjective, giving the quality of being alive to something that not necessarily has live. Ex: - En mi último viaje a la Amazonia vi muchos organismos vivientes desconocidos. Hope that helps!

Aunque son sinónimos la diferencia en uso es muy simple "Viviente" se aplica únicamente para calificar la cualidad de "tener vida" en expresiones de tercera persona, "vivo" aplica para primera o tercera persona de forma indistinta.

As I understand it, you would say "viviente" to describe something that is not usually alive. The most common phrase with "viviente" would be "muerto viviente". "Muerto vivo" would make no sense because it's contradictory. "Muerto viviente" emphasises that, even though it's dead, it is a living thing (this is getting awkward). Another example would be "Belén viviente", which is a representation of the Nativity by real people. Of course, Nativity scene is normally represented with figures, but if it is represented by real people, it becomes a living thing in some way. "Vivo" is much more common and it refers to something that, simply, is not dead. For example, "el gato está vivo" (no está muerto). "Vivo" is also used to mean "intense", "vigorous", etc. Ser vivo (this is kind of a set phrase), organismo vivo, espíritu viviente. I'm not sure what you mean with "laboratorio". Hope it helps!