Lots of potential wrinkles to this one. If Mueller's team can trace the money to illegal sources, it can be forfeited. If it is forfeited, it's not an asset that can be divided - since it belongs to the State. Vanessa could claim she's an innocent and try to keep some of the money, or, if the settlement agreement is written properly, he would "hold her harmless" and she could get equivalent assets from the rest of Don Jr.'s estate.
To illustrate: assume that since they've been married more than 10 years, she gets half of the "marital estate". For simplicity's sake, it's 100 dollars. If the government proves that 60 dollars is illegal, they'd each only get 20. If Vanessa can prove she's innocent, she could go after Donald for the other 20 and an iou (judgment) for the rest. If Don Jr. later gets an inheritance, for example, she could go after that.
If the government agrees she's an innocent, she keeps her 50 bucks, and they go after Don Jr. for the whole of the ill-gotten gains. They could also get a judgment that they could enforce later.
Note that these are all "civil", not criminal, matters, which means the burdens of proof are lower, and are technically not affected by an acquittal - no double jeopardy - although there are internal DoJ rules that generally prohibit forfeitures after an acquittal. If the forfeiture occurred before the criminal case, no problem.
A well reasoned argument is like a diamond: impervious to corruption and crystal clear - and infinitely rarer.
Here, as elsewhere, people are outraged at what feels like a rigged game -- an economy that won't respond, a democracy that won't listen, and a financial sector that holds all the cards. - Robert Reich