All of these friends of Naruto are now a part of his family which each possess the Senju's 'Will of Fire'. Hashirama's was probably at the highest level which shows how he managed to defeat a powerful shinobi like Madara who was given additional support by his brother through the EMS and by the Kyubi's powers. The 'Will of Fire' of one ninja of the shinobi alliance may be at a lower level than Hashirama's but when combined with the rest of the alliance, it becomes easily on the same level of Hashirama's.
I wouldn't be so assured if I were you. The Jubi is incomplete afterall, and it's like they both admitted they "were hasty". The Gedo Mazou (which was the vessel carrying the chakra used to create Jubi) was missing 2 biju; Hachibi and Kyubi. This is why the Jubi is not as powerful as it was when it was being controlled by the so6ps, it's initial jinchuriki. So therefore, it must have a weakness and we might find this out hopefully in the next chapter. Madara's end is coming and so is Obito's.
