MOD: Armageddon's Blade

Firstly, it's still about twice as fast as modeling a low-poly version on top of a high-poly one (or even three times faster). There's not much need for drawing; you just need to cut out a circle and a square. Secondly, the idea is that this can be done instead of a high-poly model, meaning you don't have to spend the time you would have spent on the high-poly model. You could immediately create a low-poly model and add the necessary details to the texture. I'm just trying to say that you've complicated your work by a factor of three, without any benefits to the result (or even with drawbacks). I don't know how or what you plan to bake, but if you're so sure there won't be any problems, maybe you know what you're doing.
But what's the point of transferring high-poly simple cubes and pipes to low-poly ones when you can bake low-poly models onto themselves with the same success, guaranteed without artifacts and without wasting a lot of time on the high-poly model and its retopology?

In any case, good luck!