Sorry, but you aren't getting Degrom for any combination of 3 pitching prospects we currently have (unless the Mets FO is run by Dave Stewart). Degrom, if we get him now, can likely be expected to produce about 12 WAR over the next 2.5 years. At 9 million per WAR, he'll have roughly 80 million in surplus value remaining (that figure may be low tbh).
Now I only have preseason ratings to go on, but you're likely looking at one 55 FV hitter of Riley/Pache to start with. Then add another 55 FV pitcher like Soroka/Gohara, then add another 50 FV guy like Allard, Anderson, Cumberland, Waters, Touki, or Fried.
And that only gets you to roughly 75 million in surplus value. So pretty fair overall, but that's not factoring in the contenders premium along with possibly extra for an inter-division trade. So a package of Riley, Soroka, and Allard may only even be a starting point in negotiations.