My wife is also quite loyal to the Org. This sounds like something she would do.
I believe she volunteered to feed them lunch by asking the elders to do it and mentioning how it would help you to have these highly spiritual brothers at the dinner table, (maybe some of their spiritual mojo would rub off on you : - )
The COBE appraised the CO of who it is that he'd be eating lunch with--a faithful sister and an weak brother who is troubled over child abuse situations in the JW religion.
The CO and the sub-CO talked before hand about their having lunch at your place and discussed what the COBE said about you and your wife's situation.
The sub-CO brought up the subject to try and draw you out. His wife just went along with it, or was made aware of this situation by her husband.
You were wise to keep mostly quiet and listen without getting exposed. The CO will likely tell the COBE how the lunch went and what his opinion of you and your situation was.