Are there any known issues for developing in Ionic for Kindle Fire and Galaxy Tab devices?
Is the code/assemblies and/or target Framework any different than any other android device?
According to this, seems like Amazon is not currently accepting Ionic apps in their Kindle store (even though the Kindle runs a version of Android).
As for the Galaxy Tab - since it is a normal Android device, Ionic apps ought to run normally in it. Just make sure you take into consideration the higher resolution! It can mess up your UI if you don't properly scale and test it.