Sarcasm aside, I honestly can't tell if this is an out of season April Fools joke or not. What you've laid out is a terrible plan that will require ridiculously more effort than it's worth, and isn't even possible to achieve. Setting aside how un-smart it is to place a HDD in a portable device that if dropped during operation, will kill the HDD, you can't just make a floppy drive work with a Wii.
Even if you use a modern reproduction floppy drive that can run off a single USB port's worth of 5v, and don't try to interface an ancient IDE brick drive that requires 12v over fucking MOLEX, there's no guarantee that the Wii will even recognise the drive's existance. The Wii was not designed to use that kind of storage, it's finnicky enough with regular USB 2.0 compliant solid state storage (aka: thumb drives). What would you even store on a floppy disk anyway? You can't even fit a compatible NES emulator on a high capacity 2.88MB disk, let alone a ROM for it to play as well. And if, let's play devil's advocate, if the Wii did recognise the floppy drive, the read speeds would be beyond terribad and there is a distinct possibility that all write operations would fail.
Not to mention that it's physically impossible to make this work, as the Wii cannot read/write data to 2 USB devices at the same time. It can index both drives to obtain a list of playable games if you install many custom IOS modules and do several XML edits, but the second you execute a call to read or write data to the second drive, it shuts down drive 1 so that it can use drive 2. So if you had the HDD as your USB device 1 with RVLoader or Wiiflow or whatever loader app you want use + whatever fuck off emulator you're running that uses ROMs small enough to fit on a floppy disk, and have the floppy drive as your USB device 2 (because that's the only way you could do it), attempting to run anything from the floppy drive would immediately cut off access to the HDD, which will cause a major exception (error) in the software and end up being an elaborate way to get yourself a free blackscreen.
I really hope this is a joke, because from what I've seen of your posts in discord you definitely do not have the knowledge or skills to pull off a Benheck article bait project like this. Hell, even Aurelio himself couldn't do it, it's impossible. I don't want to shit all over your dreams, it is an amusing idea and seeing it done would be really funny, but practicality forbids it. I genuinely recommend you tone down your expectations and start off doing something simple and with an established support base, like a G-Wii, so you can learn practically and have access to the knowledge and assistance of many people here who have done it before and can actually help guide you to completion.