Last one first. It's a bit simpler- a drop swirl essentially. The black was made with activated charcoal and you want to be sure you are getting black and not gray, so use black oxide, AC, or mix one of them with black mica so the batter is definitively black. In the last one, the black got a bit thick- medium trace or like a soft pudding that holds its shape. I poured about 1/4-1/3 of the black into the mold and then used the colors- sunshine yellow, orange vibrance, and one of the strong pinks (can't remember which one, but don't use a soft pink). All the non-black colors were still just at trace and pretty fluid. I pour them down a straw so they layer one on top of the other instead of blending, and pour in a pretty random pattern. Then pour the thicker black on top. It will squish some of the colors up around it. Another layer of bright colors and then pour the black in. DO as many layers as you want but leave some black to top off if you want your flames more in the middle. It's fine if you see some of the flame colors coming up around it. It give them a more organic shape. I believe I used 1/3 or less of the batter for the colors, the rest black. If you look closely, you can see how the black went in and pushed the colors around those pours.
The first one is a little more complicated. I used dividers but you can also just tilt your mold and pour carefully down the upside wall to get the colors to go into lines. In the first one, I had dividers that made 6 spaces. Filled each one with a different color (yellow, orange, pink/red) and I made each color slightly different (one yellow was very bright yellow, the other a more golden yellow, one orange bright and the other a bit deeper for instance). Use about 2/3 of your batter for those colors. Batter should be not be terribly thick so pour at trace but not at medium trace. Take out the dividers and then do a taiwan swirl. If you do the taiwan with a lot of space in the swirls, you'll have bigger swathes of each color (like the first one). If you do a taiwan that is very tight, or if your trace is very light, you'll get more color blending/intermingling (like the second). Then pour your black (about 1/3 of the batter-your call on proportions of course) on top of the taiwan swirl (I know, it seems wrong but you want the vertical cut of the taiwan) and make sure the black is sinking a bit into the other soap. Pour almost like a drop swirl so the flame colors get the movement between the black. This is done in a loaf and you cut vertically, not horizontally even though the taiwan swirl is laid out horizonally.
Post pictures of whatever you try!