Geese do not sit like a broody hen they do tend to have a stretch and go back to the nests.Young geese are not guaranteed to be good mothers, they do get confused and may let one hatch and walk off with it leaving the others to die, see another nest hatch and go look after that lot etc, but they have to learn. A gander may not be up to much till a few years old either. On the other hand they may be fantastic parents from young, time will tell.Till a goose is ready to incubate her eggs she will leave the nest for a long time, even till she lays the next egg or turning time, then she will sit.
When I bought my first goose the lady said geese live for up to fifty years and the best parents at twenty five!! Good Luck, your lake and goose house sound fantastic.