You are confusing two different things. In the case of the lepers, no one was coming forward for them, asking for them to be healed. In their case they were asking healing for themselves. They HAD to have faith or Jesus could not have healed them. You yourself have said many times God does not give grace to unbelievers.
No, I said God does not give spiritual gifts to unbelievers.
Christ himself said he gives grace to all: saved and unsaved alike.
He makes the rain to fall on the just and the unjust.
Likewise the sun: He makes the sun to shine upon the just and the unjust.
He shows both mercy and grace to both. Without mercy and grace we would all die. Who keeps our hearts beating? It is by the grace of God we live and breathe and walk, etc.
The lepers asked to be healed, not to be saved. Faith is confidence. They had confidence that Jesus could heal them because they saw the miracles they did. It is very possible that they had no intent on being saved. Everyone in the hospitals want to be healed, but some of them are very hardened against the gospel, and won't even listen to it miracle or no miracle.
The rich man's five brother's, according to Abraham, would not have come to Christ, even if one who had risen from the dead had come to see them.
And he went out from thence, and came into his own country; and his disciples follow him.
2 And when the sabbath day was come, he began to teach in the synagogue: and many hearing him were astonished, saying, From whence hath this man these things? and what wisdom is this which is given unto him, that even such mighty works are wrought by his hands?
3 Is not this the carpenter, the son of Mary, the brother of James, and Joses, and of Juda, and Simon? and are not his sisters here with us? And they were offended at him.
4 But Jesus said unto them, A prophet is not without honour, but in his own country, and among his own kin, and in his own house.
5 And he could there do no mighty work, save that he laid his hands upon a few sick folk, and healed them.
6 And he marvelled because of their unbelief. And he went round about the villages, teaching.
Why couldn't Jesus do any mighty works among his own countrymen? Because of their unbelief.
This unbelief refers to who Christ is. They denied that he was the Messiah; they denied his deity: Christ the Son of God. That was their unbelief. Take things in their context.
There are times when a person had to believe for another, as when the young girl died. She could not believe, so her parents had to believe for her. The demon possessed boy was out of his mind and could not believe for himself.
Does that hold true for salvation?
But when people could believe, they had to believe before Jesus could heal them. Jesus did not reward unbelief.
He did in Mark chapter one and in Mark chapter 3, where he healed hundreds if not thousands--all who came to him. It was out of mercy--faith or no faith. He can heal as he wills. He is not bound by people's faith. That is a ridiculous condition that only Charismatics use. And then when the sick person is not healed they cruelly put the blame on the sick person and tell them "It is your fault; you didn't have enough faith."
That is a cruel joke. The Faith healer is the one that needs to have the faith to heal, not the sick person. Thus did Peter and Jesus heal without demanding faith.
You are turning into a Calvinist, you believe Jesus heals people without faith, just like they believe Jesus regenerates someone without faith. They believe Jesus regenerates a man so that he can HAVE faith.
Jesus can heal whomever he wants, wherever he wants, for whatever purpose he wants. He is not limited by your theology. He is God Almighty!!
Healing is not equivalent to salvation.