Fromm's is a great choice! Have you also purchased the existing food that the breed is feeding Ace? Moving to a new home and family is a big adjustment and can sometimes upset a puppy's digestive system, so I would give Ace the food that he is accustomed to for a week or so before beginning the transition to Fromm's. When you do begin integrating it into his diet, it should be gradual. For approximately 5 days give him 75% old to 25% new, then 50/50, then 25% old to 75% new. If his stools become too loose, back off and wait a few days before adding in more of the new.
Other members will chime in soon, but this is what I would recommend.
As far as how long a bag will last: I have two furbabies eating Fromm's (one an EB and one Shih-tzu) and a 26lb bag now lasts a little over a month for us. I feed Mayhem (my EB) 1 cup 2 times per day and Chewy (my Shih-tzu) about 1/3 cup 2 times per day. However, when Mayhem was a young puppy (up to 6 months), he ate from 3/4 to 1 cup, 3 times per day, so a bag lasted us a little over 3 weeks.