Dofla being alife is dumb luck!
Here is why: All the toys have been enemies of Dofla or his crew. His enemies over the past ten years. He forgot about all of them. Then they come all back at the same time. Doflas mind must be overwhelmed at the moment. Think about it. Someone like Kyros wasnt surely the first enemy that came back to Doflas mind. Then he jumps out in front of Dofla. Dofla sees him. His overwhelmed mind realises oh fuck it`s this guy. Kyros is super fast. Oda didnt show us his Jet walk for nothing and the swiftness of Rebecca which she learnt from Kyros.
There is no confirmation in the manga that Law has seastone handcuffs.
There was no immediate need. Doffy kicked his ass previously. He is badly injured and got 3 bullets in his chest. Law should be on the brink of death. Dofla underestimated Law. If it wasnt for Law Dofla would be dead.
The question is why Law saved him. I am not sure about that. People tend to overcomplicate.
1: Dofla having a logia? For me this is bullshit. A string logia would be terrible and make no sense. Then basically everything can be a logia. Mr.3 should be a logia than and many other paramecias we have met.
2: Pica saved him with a stone clone? There is no hint that he did, other then the fact that he has seemed to vanish from the fight with Zoro. Furthermore it all happened in seconds so i dont see him saving Dofla like that.
3: Doflamingo has pacifista of himself? Bullshit. When Dofla goes to PH we see his people talking about him going out on his own again and many other situations when there should have been hints to him having clones walking around. Even his people like Bufallo and Lady 5 dont notice? Violet didnt notice that for 10 years? Why wouldnt she tell Kyros that this might be a Doflaclone? They have been chilling on the balcony for some time now.
4: Law saved Dofla because he needs him for something?! We see Law a few panels before Dofla gets his head cut off. He is awake and mummbling something. We know that his power is cutting people exactly that way we see here with Dofla.
Every swords that cuts in a "room" cuts like this. Law controls everthing that happens in his "rooms". We dont know why yet but i believe that he did it to further his plans or to confront Dofla about Cora san or something else.
On another note. Nice thinking by Sabo winning the tournament and opening up the basement in one move is awesome. On the last side we can see that the he is standing at the "core" off the ring while the other fighters all fall down. We will see if that is enough to win the tournament. Even if he isnt announced as the winner he will take the fruit righteously because he knows he has won. But what do the revos want in Dressrosa. Maybe plundering Doflas weapons and smiles for themselves? Excited all the way.