Hi, Mike. While I am not an expert, I would surely agree that sanding or scraping is about the most objectionable way to remove lead based paint. I really can't comment on the heat gun approach other than to say that it certainly would not be my choice for removing any kind of paint. And are you sure what the surface temperature will be?
There are several different kinds of chemical strippers. The most widely used is methyl chloride based, sometimes with other chemicals. I used this for years but never will again. The methyl chloride is just not something I want to be around. My choices for strippers are Citristrip or Peel Away, depending on how many layers of paint that there are. Citristrip is good for up to about 5 coats and is about as safe as is possible for an inherently unsafe process. You will find them on the web. The other product, Peel Away, is great for multiple paint layers but a little less safe than Citristrip. It is harder to find and more expensive than other products, but it works. You can usually find it at some home centers or by mail from places like Woodcraft.
Hope my opinions have given you some direction. Henry in MI