I guess there is also the possibility she is wearing the same clothes under the cloak but you're probably right and Charle's vision is about present Lucy.
On the topic of future Lucy, I had a theory of why she isn't sure about her memories. Maybe future's Lucy's memories are blurring. The fact that she came to the present means that slightly different decisions will be made, making there will be a slightly different future from that which she came from, what she remembers doing could be slightly different from what she did do. For example, when future Lucy was in the scenario originally, maybe they all ran right into the room where Eclipse is located. But, this time around, because future Lucy is present, maybe they won't run into the room with Eclipse, instead, for argument's sake, just Natsu will run in there causing present Lucy to have a different experience which will in turn cause future Lucy to have conflicting memories and have issues recalling what happened between the present and future. I am sorry about being unable to accurately articulate my thought, but this always is the issue with time travelling in any literary work, its difficult to comprehend.
I also had another thought, it is likely to be wrong but is there any chance that Minerva is connected with Zeref and Acnologia? After all, Mavis recognized Yakuma's Spell of the Eighteen Gods of Battle - where did Minerva learn it (there is always the possibility that she read about it)? Additionally, Minerva seems to have her own agenda, by having saber tooth win the games she may be able to accomplish something else.