I would pay the £10 upgrade before you go as hopefully by the end of the week she will have progresses and if not, it's only £10 rather than x3 as much in the resort.
In terms of them meeting up at lunchtime, it depends on which ski area they are in - if on the Rila side, it will be fine as all restaurants are at the bottom, but if your husband is taken onto Yastrebets he will prob eat at the Finish Line and she may not make it over that side all week...