Good question, Donna does say in one of her emails, as I recall, that when she left in the Pearl Harbor divorce she took a bed and two chairs. In Epstein’s book, I believe he says she took the boys’ beds or cribs.
As for after the murder, Wendi herself testified on the stand, as I recall, that she just took a few things for herself and the boys when she went back with her parents to South Florida, because she wasn’t planning on staying. If that is true, then it certainly is possible that someone removed whatever furniture there may have been after she left, or it’s also possible that the house was leased to the next tenant furnished or partially furnished after she vacated it. In my experience in college towns, people are always coming and going, and so furnished rentals may be common.
Hypothetically it’s possible that the South Beach condo was leased at least partially furnished as well, in which case the family would not have needed much furniture. It’s common in my experience for these “investment” or “second home” places in South Florida to be leased at least partially furnished with the absent owners’ stuff.
I do recall that on one of the Bump calls where Donna is discussing moving to a new unit in the Icon, she says she doesn’t have much furniture to move, just a bed and the piano. The photos that I’ve seen of the CS house before it was sold look to me like a lot of the old 80’s style furniture is still there.