In the 2 Delta Platinum scenario, one trip next year would be:
2 paid tickets, two companion tickets at AF*2, 1 ticket on points. The fees are $195-$100 statement credit (and I then have a $50 Delta gift card), so $95 in first year, and $195 in second for a total of $290 in fees for 70k bonus points, one ticket on taxes, and a $50 gift card.
Double it for player 2, plus a 10k point referral bonus, and that is $580 in fees for 150,000 skymiles, two tickets on taxes, and two $50 gift cards.
Quite a bit of an outlay. I need to price some flights to see the savings on the routes I might want to take.