HEY OBITOGOKU KAKASHI OKAY PEOPLE I WILL GIVE YOU SOME BACKGROUNDSYou must be registered for see links
The only reason I say Kaguya might take over is because she was introduced and you know how Kishi is with new characters. Also Kaguya is a seemly powerful individual who started it all so it should end with her too but it's just speculation at this point.
I don't believe he is a puppet. Maybe his greed for power just resembles Kaguya. On the other hand, regarding the latest manga chapter, another idea might be that such acquired power by Madara might trigger Kaguya's some sort of appearance...out of him?
If he is no different from her than why be a puppet they could be allys madaras will is to strong to be used by anyone he would attemp to kill her before he becomes a puppet
He (we) still doesn't know the full extent of her powers. he got saved by absorbing the tree and who was guiding him? Kaguya.
They are same in the case of hunger for power. The difference is both will try to get more power and in such case they won't be allies because Kaguya was hailed as the goddess.
I never thought of Madara as a puppet. I saw him more as Kaguya's avatar/ her will personified if you will. She has no desire to control Madara, she wants to see him succeed where she failed. She has no body if her own(that we know of) so she is guiding Madara with her will/chakra
Think of Madara as the son Kaguya has always wanted.