I might be wrong but, I feel like Robert Waggoner has talked about this. Yes I totally agree it is possible and I have personally tried this a few times. The only thing for me is that when I know the situation isn't real I find the experience to have less of an effect. Just like when I am in VR I don't act the same way to NPCs as I would to waking life people nor do I care what they think. I see DCs the same way. Actually, I see DC's as tiny aspects of myself. Sure it's great practice but doesn't have the impact I need.

Non-lucid dreams have actually helped me more with my fear of public but they are random. I guess you could try to incubate a non lucid though.

Honestly, the best thing for my fear of public speaking has been just doing it in waking life. It's an aspect of my job now. I will probably always struggle with that but I get better every time.