Elegans require lower ambient humidity than do platynota (and thus require a little more vigilance). I'll defer to others on the lowers bounds for humidity levels for the Burmese, though.
Beyond keeping them together as juviniles, thats up to you, assuming it is feasible, husbandry-wise. I know of at least one instance copulation between a mainland female and a male Burm. (But I'm sure its been happening for thousands of years). I'm not too sure what happens after that.
>>I recently acquired a couple of Burmese Stars and am interested in a pair of Sri Lanken Stars. As these are just juveniles, can they be kept together until they are older and possibly beyond? There requirements and habitat seem to be similar. Thanks for any suggestions