Can Madara copy shinsuusenju ?

[Draphsin]

No, he has no senjutsu

He can copy any other jutsu that hashirama has, as demonstrated when he created the dragon

 

[Mitarashi]

HAHAHAHA!

What now.
Can he use Senpou; Mokuton shinsuusenju?

 

[Draphsin]

Yes now he can

With the addition of senjutsu, madara can control, cast & utilize nature chakra, proof is when he sensed sasuke's mangekyou while blind.

Madara can use senjutsu, or more accurately he can control it, he has knowledge on it & can cast jutsu without actual handseals.

His shinsuusenju would be smaller, but he can use it.

 

[Mitarashi]

Yes now he can

With the addition of senjutsu, madara can control, cast & utilize nature chakra, proof is when he sensed sasuke's mangekyou while blind.

Madara can use senjutsu, or more accurately he can control it, he has knowledge on it & can cast jutsu without actual handseals.

His shinsuusenju would be smaller, but he can use it.

Smaller?
I doubt that. Uchiha have a more powerful Chakra, Senju had more powerful "Life force" and Madara has both. His would be stronger, I'd think.