Be extreemly careful lime will mark the oak. I would do the walls first, then lay floor. I would also trap an air barrier in behind the bottom of the wall with expanded metal rendered over, and trap this under the new floor boarding. Then form a plastered skirting with thick paper laid on the floor to protect the new floor.

I recently laid an oak floor up to a very curvy stone wall; I did a kind of horizontal skirting board, by leaving a 10mm expansion gap between boards and wall, which I covered with narrow strips of the flooring timber, cut to fit neatly against the curves of the wall but with a neat straight edge on the room side of it. The floor was laid on a chipboard sub-floor, so I nailed the edging strips down to this through the expansion gap, if you see what I mean, so as to allow the floor to move independantly. It looks nice and neat, although doing it that way meant that a tiny bit of floor space is lost - you can't stand furniture right up to the wall - but the wall is so bumpy that it doesn't matter in practice.

How about folding some plastic sheeting around the edge of the oak. Plaster down to that and cut it back when the plaster is dry?