We know there are 7 non-giant worlds orbiting the star.
That is all we know. This could be earth-like, have water or anything else is all conjecture and wishful thinking
Not entirely. For example, we know how far they are from the star, and distance is related to temperature, so knowing the star's output one can compute whether or not a planet is within the "Golidlocks zone".
Further, the size of the planet itself can be determined from the intensity drop-off during transit; and in this special case, the presence of multiple planets in close proximity allows estimates of each planet's mass -- and thus one can infer its density and hence its general composition: gaseous or solid.
Finally, it's already possible in some cases to characterize the composition of planetary atmospheres; that it's not been announced for these may be due to the fact that it just hasn't been done yet; or they'll have to wait until better technology comes along.