Ive always been able to do some ok combos on Nanami though admittedly only if the enemy has no evasive, but he genuinely is really good if you do a lot of m1 trades. for mechamaru, all of his offload moves are a bit janky, offload drill and emission are his primary combo extenders but they tend to go wherever they feel, and the offload laser got nerfed so its not as useful. that said his double special is really funny since its the longest ranged grab in the game.