Both the undergown, and using hooks and eyes for keeping the skirt and doublet together, are Anne of Wokyingham's ideas. See other post about undergown!
The hooks and eyes are well attested in English clothing, for men and women, keeping doublets attached to bottom halves.
For this outfit, they are very practical solution. The skirt weighs a ton, and hanging it off the doublet distributes the weight on my shoulders rather than my waist.
The doublet is very short and fitted, and without some anchoring, rides up easily; the skirts wil provide plenty of anchor!