The first loan scenario looks to be the best. For an $8 a month difference why would you take a second loan? You didn’t give a lot of info about your plans for the hom ebut I dont see a reason why you would take the 80/20, again its only saves you $8/month and the closing costs are higher
Watch out for the 100% one loan scenario. Is there a pmi payment on top of the monthly payment quoted? If so its probably actually a higher overall payment. The pmi wouldn’t be terribly much though, maybe 40 or 50bucks.