There are so many whit doubles that occasionally have red flecks, you have a hard road ahead trying to identify! I'd say right off the bat though that if the foliage doesn't match Festiva Maxima to keep looking, it's not that variety. Every single aspect on a plant will match if they're the same variety with small deviations due to difference in soil makeup. Sports do pop up where part of the plant might display a different aspect, that happens more often on hybrid plants where different peony species or genus are crossed, not as much on what is considered a lactiflora. I'd your wife's plant is in the same soil as the Festiva Maxima your comparing to and the foliage is different then it's not a contender as a match.
I got Mrs A.M. Brand from Countryside in 2018 but it's in a bed that has been overcome with blackberry brambles and probably won't be cleared out for a while yet. Have no idea what has and has not survived in it. LG, did you get that one from Countryside as well? I know our tastes are fairly similar and our orders overlap a lot.
