“... will some of our stuff be so ruined we’ll have to replace it rather than just get it up and running?”
The size [area]/intensity of the EMP is the most critical.
Most ANYTHING/EVERYTHING in a homeoffice/any non-FaradayCage structure will be toast unless it is in Faraday cage structure at the time of the event.
As for replacements, that will be mute.
Electronic devices do not go out “some” - it’s either OK or dead.
If the “large++ event” occurs there will be no replacements for you or anyone else -what happens at your place will occur in all the others too.
And unless you have a generator that did not fry and you have the fuel to drive it, then where will you get electricity or fuel.
I suggested reading “One Second After” to get a vivid sense of what the situation will be like for several years to come.
Hollywood has done a VERY poor job of accurately describing the aftermath but their “best job so far” is the TV series “Jericho” which you can purchase or get from your local library.
FYI, I’ve been researching this matter for 5+ years and had been in preparation for writing a book on the technical aspects in deep detail.
OSAfter book has the “gory details and some technicals” down well enough.
I have since pull off the project for more pressing and immediate concerns.
Will you have a chapter on things families can do to prepare - keep a radio and some ‘spare’ parts for (?) in an old microwave oven in the garage... etc. Or things a small city could do? Or a medium size one? Part of what people want is to feel they have some control...