the diagram above shows the possibility of separating the humbucker into singles, so you can similarly connect two singles into a humbucker... if my reasoning is wrong, there is one more option... this option is a double single.=, instead of the humbucker I mentioned.
Your reasoning is right. It's just that a lack of clear explanations don't help us to help you. ;-)
At least your last post
suggests to me that you want to connect a single coil with another single coil, RWRP ("Reverse Wound & Reverse Polarity". As a matter of fact, you need a second single coil to be RWRP with a first one if you want both to form an humbucker).
As the RWRP single coil is
usually the mid pickup, I
deduce from your answers that you want a switch allowing to put the MID single coil in SERIES with the bridge one.
I still don't see how a 6 poles ON-ON-ON switch could do that AND put the bridge pickup in parallel with the neck one (I
guess you want parallel wiring when adding the neck PU, because if it's in series, it's not different from the "humbucker" option that you evoked)... :scratchch
For the record, my main Strat is fitted with a push-pull tone pot that I've hacked to do what you appear to want: when I pull off the pot, it puts bridge and mid in
series. The pot itself has been modified to be a no-load control and acts as a blender for the neck pickup, putting it in
parallel with the bridge pickup... But I need two separate controls to do that (the pot itself AND the 2 positions push-pull switch under it).
Also keep in mind that mid + bridge in series in a Strat don't sound like a regular humbucker. It just gives a fatter version of position 2. It's usable for Brian May sounds, not much for more traditional tones (unless one moves the mid pickup just next to the bridge one, as on Robbie Robertson's Strat).