Using regular flour & active dry yeast?

The recipe works because it starts with a tangzhong. That's a special technique that esssentially cooks some of the starch so it holds liquid and makes the end bread soft and pillowy. It is then added into the dry mixture while still pretty hot, which is why the cold milk is essential. The instant yeast, in dry form, is better able to mix in completely and likes the warmer temperature to get going. Regular yeast may not do so well with that temperature, and also needs to be rehydrated first. Swapping the bread flour out for regular flour could also pose challenges. Regular flour has less protein, which translates into less gluten, than bread flour. It's going to affect the texture of your rolls. You can do it, of course, but you may have to knead the dough for longer to get the same texture of dough, and it may be a bit stickier because it may not be able to use or hold all the liquid in the recipe. So you might need more flour. I would be more likely to substitute the regular flour for the bread flour, and less likely to swap out the yeasts. The order you add in things, and do things is rather important to the overall success of the recipe - and you don't want to alter that much. You could still try, using some a small amount of the milk to rehydrate the yeast into a paste, rather than a liquid and adding that in when the temperature permits. Just don't expect quite the same chew in the final rolls, and perhaps not quite the same rise.