The fork feels overly stiff because it is. Cheaper and easier to build them that way. Carbon forks are not all the same. Some do feel like they accomplish the vibration dampening they claim, most are just dead slabs of plastic and very stiff. Again because that is the easy way. Best way to do this would be a custom steel fork with light gauge small diameter blades and lots of curve and reach at bottom of blades. A full custom fork will cost a third of what the Lauf fork recommended above costs. (Lauf is otherwise a good idea.)
The Rene Herse tire recommended above would be great. I use them and wear them through without flats. City of Chicago, plenty of glass here. Front tires flat much less anyway. Keep the pressure way down and the tire squirms over glass. Hard tire punches the glass through.
Don’t know exact spec on your example of a 7.1 but it probably has a straight bar. Bars that sweep back, turn back, put the wrists in a completely different position. Most will find the turned back position more comfortable. Straight bar was in imitation of mountain bikes. When crashing through boulder fields it is easier to keep hands on the bike with a straight bar. Since your wife is not descending singletrack at speed she does not need an MTB bar. Since she already has special needs try everything. It is cheaper than more surgery.