Reading various tutorials I was wondering if will be possible in Hoidini to create a “smoke man” where actually the man figure is not visible and is fully composed by smoke such as in this image

I can't tell you exactly how to do it but stuff like this is entirely possible in Houdini. There's even a Pyro shelf tool for it:

https://www.sidefx.com/docs/houdini/shelf/pyro_wispysmoke [www.sidefx.com]