As for them being an all logia group with strength similar to CP9... if that is the case then they are by no means a threat of any sort to the strawhats. Well, under the right circumstances or a surprise attack scenario they could be a problem but in straight fights they would simply be people waiting to have the crap beat out of them.
Don't underrate the possibility of a Logia user who can control their body mass really well when using their fruit and in their Fruit's state.
It is by no means an ass-kicking for them. Considering only the Monster Trio can hurt them.
If a Logia meets any other member then its a death for an SH member.
I was talking about a team comprised of logias but with the strength the previous CP9 had. I am not underating logias per say, I was trying to make the point that the previous CP9 wouldn't be to the current strawhats a huge threat. The monster trio can use haki and they have more than enough strenght for that task. As for the others its a matter of them finding a way to deal with the elements potential logias control. Franky has lazers, fire and perhaps a couple other weird weapons at his disposal, it wouldn't be weird if he could take advantage of elemental properties to his advantage. Brook has his ice, there are probably a few types of logias he could force solid by freezing them (say, he could freeze caribou's swamp solid for example). Nami has the greatest amount of elements at her disposal so far including thunder, water, heat and who knows what other force of nature. Ussop has explosions, a variety of man eating plants (say, he could have caribou eaten or something or use fire to somehow affect certain kinds of logia).... In the end a proper enemy for the strawhats can't be just a fruit, a fruit without a person with actual power behind it is not a big deal. CP0 being as strong as CP9 with the exception that they are all logias would just be a repeat of ceasar so to speak, a strong fruit with a weak owner....