One thing that has to be noted in regards to Lee's influence.
Lee was not able to convince Davis to let him keep all five of Pickett's brigades as of the Gettysburg campaign.
Lee was not able to get Cooke and Ransom - instead getting two inexperienced brigades under in his words "uninstructed" commanders.
So while Lee would undoubtedly argue for concentrating more with his army, one has to remember his actual success at convincing Davis to do so.
In my opinion, what the conference needs is not so much to hammer out overall Confederate plans - but to figure out how to coordinate things.
Two things come to mind:
Should Polk reinforce Johnston to the utmost of his ability (which may include even more men than he historically took)?
Should Forrest (at this time Lee - as in Stephen D. Lee - is in command of Polk's cavalry, it must be noted) be kept where he is, or transfered to the AoT to take Wheeler's place, or is it better to have him where he is?
Also, and less urgently: What is to be done with the mess of troops (broken bits of Morgan's command and so on) in East Tennessee? This is not vital, but it really would be good to make sure it can contribute - the Confederacy cannot afford to squander what manpower it has available.
There are other issues, but while the conference would be unlikely to produce a dramatic change in strategy, it could produce a better understanding of how things are situated and what people are worried about.
If for instance the overwhelming majority of Federal forces in the West are facing Johnston, that means that the other areas can and should be stripped to the bone - assuming, that is, that they would do more good with Johnston than causing havoc seperately.
It would also provide an opportunity that would hopefully encourage Johnston to speak freely about what he was dealing with. Johnston (or anyone else in his position, this is a comment on the situation the AoT is facing) needed to explain his plans (at least in a general sense - planning on holding at Dalton, planning on drawing Sherman into Georgia, planning on...whatever), his worries, what he feels he can accomplish (and if he's convinced he can't do anything, we have a problem), and so on.
It is said that Pendleton's report supported Johnston's assertion that his army was in no shape to attack. This is true. It is also true that Pendleton's report described Johnston's army as no worse off than any similarly situationed Confederate force.
So all of this needs to be understood and whatever decisions are later made once the campaign starts will be done based on a clear and mutual understanding of what problems and resources the Confederacy has.
It would take, as a reasonably safe conclusion, roughly 2 to 1 odds to beat a Confederate army in the field. Maybe more - and this assumes competent Yankee generalship, of course - Banks has far more men than Taylor but lost. If the Confederates were able to ensure that the areas to be concerned about (primarily Virginia and Georgia) are facing more favorable odds, it is possible that they could deflect the Union thrusts that would be made.
However, to do that would require understanding where concentration is needed...which ties back into the fact that Davis and his generals really need to make sure to be clear and informative with each other. There is no possible hope if that is not achieved, there may be a hope if that is achieved - even if nothing fundementally different is done, having that as a basis allows for making the most of the situation.