Of course Minato couldn't teleport the entire SA in base. He was panting even as Kurama's host, and Tobirama's reserves don't come close to a Kyuubi host. That Minato was still Kurama's host, he was just in his base state. Not to mention the fact that Tobirama didn't know Minato wasn't a host while he was alive, so he had no reason to state something like that when you consider that in Tobirama's point of view Minato could have been a host for his entire life, but even still, what Tobirama didn't say is irrelevant.
No because just having more chakra doesn't mean you can do something, you need to have the skills to do it as well. Look at Kakashi in the beginning of Shippuden and Pein arc Kakashi, both have roughtly the same amount of chakra but Pein arc Kakashi is more skilled at using his Kamui than Kakashi from beginning of Shippuden. Kakashi said Naruto had 2x the chakra that he did when they were training in nature transformation, Jiraiya has more chakra so is Jiraiya more skilled with shadow clones and Rasengan?
Minato's base Rasengan is larger than Jiraiya's and Naruto's base Rasengan so is he better at Rasengan than them both who were making Oodama chou Rasengans? Minato is just more skilled at FTG and Tobirama said as much. Having more chakra doesn't mean he can accomplish such a feat without the skills to do so. Naruto had KM huge chakra and had speed comparable to Minato but he wasn't as skilled and well trained in using that speed as well as Minato as Yamato said here
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.
Also Edo Hashirama who isn't at full power compared the chakra that both Kurama's were giving to the alliance, of course Yang Kurama was out of chakra and had to borrow from Yin Kurama prior to this, but the amount they both gave to the alliance was much more than Naruto gave to the alliance alone and Tobirama's chakra is up there as well, just not as high as Hashirama's. Tobirama's chakra was high enough as a Edo to scare EMS Sasuke, Juugo, Orochimaru and Suigetsu
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and that's not full power.
Plus he wasn't going to be FTG everyone, he was going to be doing ninjas on the battle field but he can only do a small hand full and he's using Minato as a medium to do this. The next generation will always surpass the last remember?