Going from 12 to 7 means Giants only drop 5 slots instead of 10, which may make them more amicable to making the deal. It can be done with a similar haul to what has been rumored as our offer to the Giants in the first place.
Trade 12, 53, and a 2019 4th for #7 (that's a 9.6% premium on their pick, in line with past trades).
Trade 7, 22, 96, and a 2019 2nd for #2 (that's a 43.9% premium on their pick, in line with past trades).
Bills would pick have a pick in every round in 2018, and have a pick in every round except the 2nd in 2019.