I honestly see the match up going in favour of Jiggs to some degree. Sweet spotted Fair always knocks Snake out of his Cypher, and if for whatever reason he decides to Cypher onto the stage instead of clinging to the edge, he's eating a Roll Out and is back to square one. Attempting to KO snake into the blastzones is not the objective here, as you will likely fail to do so with Snakes obsurd weight.
Snakes main weapons against you are his Mortar Slide, His FTilt, UTilt, Mines, and Nades.The slide allows for him to compensate for the lack of mobility he has while facing Jiggs, as it is hard to punish and quite fast. The UTilt WILL kill Jiggs, so avoiding it is a must. FTilt also has insane priority, so it should not be challeneged. Nades will be cooked and tossed to take advantage of Jiggs lacking a projectile of her own, and the Mines will be placed in hopes of blowing you off the screen, although this likely limits Snake more than Jiggs since she will be aerial 90% of the time.
Your main strategy here is to space Pound and Bairs properly when the chance is given until Snake is at a proper percent to be moved along the stage through the use of Fairs and Throws. Jiggs is the faster and more mobile here, so capitilizing on this fact and abusing it is a must. Stay aerial to avoid Mines, and Air Dodge appropriately to weave through the FTilts and Nades being thrown your way. Avoid Rest at all costs, as it will serve you no purpose in this fight. Once you've pushed him to the edge, he is yours. Fair him every time he uses his Cypher, and predict his intentions. If he plans to cling to the edge, push him out further and Edgehog. If he tries to recover onto the stage, a Roll Out will likely push him too far away from the stage to recover.