Depends on state law. Both of those options can be challenged in court. In Lava’s case, it probably wouldn’t make any difference because he doesn’t own the leasehold–his Revocable Family Trust does. The trust doesn’t die when he does. Thus, even if one sister wanted to challenge his will, all she could even hope to get is whatever wasn’t already owned by the trust when he died. It doesn’t sound like he has that sort of family dynamic anyway.
“Whatever wasn’t already owned by the trust when he died…” is covered in my ‘Pourover Will’
" A pour-over will is a legal document that ensures an individual’s remaining assets will automatically transfer to a previously established trust upon their death’.
Also, the beneficiary of the retirement plans is the ‘good’ Sister. This is why I think an estate attorney is critical to ensure that just what you want is covered and legal.