OK so I've given considerable consideration these six days now concerning a choice between the Masakage and Kagero. Well actually I've been watching a lot of public television this past week.
But never the less I have a reasoned conclusion to the present conundrum and here it is:
The Masakage while a great value has some serious drawbacks for you, as you have described your situation and needs. Firstly the only knives in there line you should be considering are the Mizu, Shimo and Yuki. The Mizu and Shimo are carbon clad carbon. They won't provoke your husbands allergies, but they will rust if not immediately cared for after each use. The Yuki is stainless clad carbon, a little better on maintanence, but we don't Know its stainless's composition.
These knives will get a little sharper than the Kagero, but their edge retention is no where near as good. Also, they have very thin edges, and this is a concern for someone who does not have very good knife skills nor any experience with thin edges such as these.
The Kagero is thin behind the edge also, but less so than the Masakage, It's SRS-15 steel not only takes a great edge, it holds that edge amazingly well. You could very conceivably go a whole year without sharpening given ordinary home use. The only question is what the stainless cladding composition is, Jon Broida will probably know this.
All of these knives are symmetrically beveled, and so ambidextrous.
Given a nickel content in the Kagero's cladding, there are mono-steel knives in Swedish stainless (19c27 in particular for it's edge holding) and Japanese Ginsanko. These will have no nickel.