Those under the hump bolts aren't that unique. I'm sure you can find something from Pro-Bolts that will work perfectly. You might not find it by using "Hayabusa" as the search term but those are just ordinary button head screws. Measure the stock bolt's head diameter, thread width and length with a calipers. If you can't find button heads to match that from Pro-Bolt, they've scaled down a lot since I last bought from them a few years ago. I know they had the Frankenstein bolts. ...also, Pro-Bolts sells threaded sleeves that might work as a shoulder if that's what you need, look under "Ancillary". I don't know what a locking mechanism is but if it's just a few pounds, I'd go with aluminum. ...much less expensive and half the weight of Ti. If you're supporting considerable weight or require higher torque, Ti is probably the better choice.
I was actually going to replace those mudflap bolts under the hump with plastic. I've ridden the bike a number of years with no mudflap bolts under the hump at all. ...might as well go with the lightest weight option because those are just there to hold the mudflap in place so the fairings fit perfectly.