If we cared we could probably detect their former presence by evaluating the percentage of rubidnium present in the sand used to build the dykes in Nederland.
This will certainly happen to Chicago at some time in the next 35000 years. Archaeologists will then postulate a predecessor civilization that sent missionaries South to build the ruins of the complex on top the hills at New Orleans.
Very likely. Might be interesting although it wouldn’t have much value since the ownership records are also long gone. What is interesting is that the moose emigrated from Asia to Alaska at the same time as the migrating bands of hunters about 12,000 years ago. A wildlife biologist from Univ of Alaska just got an award for proving that.