Cerdan takes this one, bad style matchup for Sumbu here. It`ll go the distance more than likely due to Kalambay`s defensive acumen and good legs, but with his low punch output and not having enough power to discourage Cerdan my feeling is he would get outworked as he will be focusing too much on defense due to Cerdan`s aggression to mount any significant offence over the course of the fight. Cerdan by a 9-6 or 10-5 type of decision.
My pick is sort of in the middle of both of yours. I think Sumbu's movement and skill will see him take a lot of early rounds but over the 15 I cant see him holding out Cerdan who will be pressuring hard from the first bell. Marcel will just bore in and wont even bother trying to battle a guy like on the outside. Kalambay's lack of punch output will be his undoing and his greatest asset will probably work against him. He was such a great defensive fighter that he often just didnt throw enough and lacked an offensive mindset when sometimes it was needed. Very close maybe even controversial decision but Cerdan takes it over the 15. I was only watching Zale-Cerdan just last night incidently.
Kalambay´s defense would pose some problems for Cerdan but he wouldn´t be able to take his pressure for 15. Either Cerdan by UD or by TKO late in the fight.