Yes, of course, these are in different categories. But, if the definition of a tonal language on wikipedia is correct, they both signify that BCMS is tonal.
On the second issue: I am not a linguist, and I am not saying that people wouldn’t understand you if you use bêla where you should use béla – they would, from the context (a lot of times, this is the case with “a”/”the” as well). I am saying, there is at least a kernel of definite/indefinite distinction there. I grew up in Bos. Krajina and in that accent, the distinction is very audible. But I don’t know if that’s the case elsewhere.