We are renovating a garden with very old grapevines. The house is from the 1600's so the vines could be any age.

The new design calls for lowering an existing pergola which is covered by ancient grapevine by 3 feet and changing the soil level around the root of the vine, fixing a stone retaining wall against which other vines grow and for a path where currently a line of grapes grow.

What are my options regarding incorporating the grapevines into the new design?

Can I increase the soil line around the root of a grapevine or will that cause rot?

How can I best protect the vines growing at the retaining wall during masonry work? Is my best option to prune them all the way and hope for regrowth?

Can I transplant the old vines that are in the way of the path? They are quite thick.