This is one where there is a choice. You get to choose which are the pieces of wood you want to keep stationary, and which are to be allowed to move, and you glue accordingly. In this case, it sounds as though you have allowed for movement between the boards within the overall width of the table, so you are expecting the outermost boards to remain where they are. Therefore, those outermost joints are the ones to glue, and the inner ones should be left dry. The other way of tackling it is to make the table top tight, and thereby expect that movement will be outwards from the centre. In this case, you glue the central tenon/s, and leave the outer ones dry.
As for the pegs.......there's not an awful lot of need for glue. They don't generally come loose or fall out. But if you put a dab of glue around the top rim of the hole just to be certain, but avoid any excess dribbling down into what is otherwise a dry joint, then you should be fine.
