I would have preferred a Panzer IV over a Panzer III, for the reasons stated previously by myself; however, the Panzer III is a respectable and logical choice too, and appears to have garnered approval in this community at least. I think it will be fine.
For the second tank, I would still prefer a Tiger I. Iconic, produced and used in significant numbers, visually different from the Panzer III, different choice from the WoTC OOB Panther, and a popular choice within this community - seems like an appropriate choice to me.
@ FMG - Any confirmation as to which Panzer III variant will be represented by your sculpt? An early Ausf. A-D variant, or one of the later variants? Personally, I would choose a E/F variant, but I do admit that most Panzer III variants would look very similar at this scale.