Hello! I am not sure what the blue tongue lizard is, but I had a bearded dragon, for many years (until I traded her for my Parrotlett.
Bearded Dragons get pretty big, as I am sure you know.
I really don't know about keeping them all together...I would think, a better option, would be to keep them both in separate tanks.
I suppose the things to think of are...
a. Will the tank be large enough?
b. Are the temp requirements the same for both species?
c. Will one eat the other one?
d. Are the day/ night cycles, lighting requirements the same for them both?
I must say the Bearded Dragons are really awesome Lizards....mine was named "Puff" and I had him several years.
Right now, I have a breeding pair of Leopard Gecko's who do not get any live food at all, but live on Hikari Cichlid (fish) pellets.
They are at least 12 years old, but I cannot pinpoint their exact age.
Anyway, good luck with your new critters.