Can Pure Titans Be Saved?

There is no specification on the manga or anime about that. But it seems that any "pure" titan as long it gets the spinal fluid of 1/9 titans is able to go back to being a human no matter how long it takes then in their pure titan form.

Can pure Titans become human again?

Basically no, there is no human in there, probably because like Legends Awaken said, they are completely fused with the body. But the important part is that Hange, Eren etc actually did check it in the anime, by tying a titan down, slicing him open and holding his slide open with ropes and hooks.

Can pure Titans heal?

Regeneration. Galliard and Pieck regenerating Those with the power of the Titans could regenerate their bodies, as long as they had the will to live. They were even able to grow back their entire head in the event of a partial or complete decapitation.