I think that there should be an option, perhaps a key shortcut, to include effects sends from individual tracks in a group folder when soloing it. This would emulate the behaviour of solo on normal folder tracks. This would also be useful for bouncing stems and including their send effects. I realize that ideally the send effects channels used by individual tracks in a group should be included in the group itself, but that requires a lot of ahead planning and might not be practical. By the way, has anyone thought of vca folders, to further complicate matters? 
I am not sure whether this is a bug or a design oversight but it surely would be nice to have the same behavior with the new folder groups as we have with the traditional folder & group combo.
My workaround is to initiate the sends which are used by the tracks in the group folder on the group folder itself and turn them down to infinity, works perfectly:
That is indeed a good workaround, as long as you keep a similar send configuration on all the tracks. If you are assigning many different send effects in your project and are using over the standard total of 8, I think you might be out of luck.
Usually in a groupfolder I dont have that many different tracks with many different sends. So it might be a leadvocal group with maybe 4 sends a Guitar group and so on.. for me it works out ok, but I see the Limits for more complex setups.