I'm sorry this has happened to your little girl. I admire you for trying so hard to cure your baby.
I can honestly say I have no idea if she can be cured. If she has many tumors they might have spread to other parts of her body. My grandfather had skin cancer. They removed the tumor, but it was too late. It spread around his body and caused him to die.
If something goes wrong during treatment she may die sooner than she would have naturally. From my understanding chemo is a very long, grueling process that can cause lots of pain. In a little critter so small I don't know if it would be worth the risks.
I'm all for you trying to save her precious life! I admire what you are doing. I just want to put the idea that maybe it is her time? Maybe it is better to let her enjoy her last few years in peace?
On the other hand you may be able to increase her life span. That's up to you to decide if the risks are worth it.
I don't know if cannabis would help. I know I once had a very shady conversation with a guy who told me he calms down his blind glider by smoking around it.
I hope someone can properly answer your questions. I'm sorry you have to go through this. Please keep us posted :)