I have to agree with Master Yang, I wouldn't do this a lot until you have built up endurance, chi circulation, song, and jing. It will take more out of you than you realize and could be detrimental to your health. I do need to remember to put in the caveats....
Build up to this SLOWLY and with a great deal of respect for your body. Listen to it and when you are tired, stop.
It's an exercise to practice the correct, precise deliverance of power. You must use all the principals of TCC in the punching, plam striking, finger striking or it will not work. You must concentrate the jing into one, very tiny area (the flame), and you must deliver it with precise timing or, again, it will not work.
You must be Song, your spirit must be raised, your chi must be circulating freely, your intent must be focused or, again, it will not work.
Yes, the Yang forms used to have fa-jing expressed throughout. YCF smoothed them out, along with bringing them up quite a bit from the low forms they used to be. Yes, I once learned an "old Yang" form, a LONG time ago. It wasn't that different, really, but it did have faster and slower timing throughout, leaps, kicks and fa-jing inherint. Unfortunately, after studying Wu style for over a decade that form has gone right out of my head and body, though it does persist in sneaking back in when I do my YCF forms from time to time. There are a few places where it's all I can do to keep my feet nailed to the floor instead of leaping...
But I digress.
No, fifth generation Wu style does not express fa-jing throughout. However, I did learn what was called the "Fast Form" from them and the fa-jing is expressed throughout this form. I have described it in the past, it's full of the same leaping, kicking, fa-jing expressing forms as the old Yang form I learned, in fact it was very, very close to that form, so I do have a good basis for comparison to more modern Yang forms. Again, it's not that different. The biggest difference I've noticed is that I'm not exhausted at the end of the smoother forms that emphasize chi circulation instead of fa-jing.
All the weapons forms I learned from the Wu's maintain fa-jing, as well.
Do the Yang weapons forms not maintain fa-jing? I don't have any idea, as I haven't studied one yet. I'd be amazed if they did not, but then again... maybe not anymore. I'm getting too used to the differences to be "amazed" anymore. Surprised, maybe. Curious, definitely. But I'm not amazed anymore.
I can't answer your question about Snake Spits Tounge in Wu style, there is no such form. I haven't found a correlary form in Wu style to that one, so I can't answer to that form directly. However, as stated, the fifth gen hand form of Wu Kwong Yu does not fa-jing anywhere in the form as practiced.
And I would be hard pressed to describe Secret Sword Hand to you if you don't allready know what it is.
If I had the fist clue how to get pictures to copy into these posts, like others do, I have two pictures of the late Wu Yan Hsia that show Secret Sword Hand perfectly, along with a taste of the Wu Gim (sword) forms.
If someone will tell me how to insert those pictures, I will gladly do so.