And here you are completely wrong. Finiteness of the universe disagrees.
I am not sure what "finiteness of the universe" means in this context. Could you elaborate why that immediately says particles must be in two places at once?
You are wrong again. Stop. Double slit experiment has been duplicated using *individual photons*. Yes, one photon fired at detector at a time. ONE. No more, just ONE. After waiting sufficiently long, interference pattern was produced on the detector. The photon appears to have interfered with itself.
The photon does appear to interfere with itself, but only after sufficient time. Is it really interfering with ITSELF? The experiment description on the page you link to says that photon is absorbed by an atom to knock off an electron, which starts an avalanche, and we read the resulting current as a detection. Now, the original photon has been absorbed, however, anytime an electron accelerates it releases radiation (brehmsstralung). So it actually sounds like the photon is causing (a) a current to form, and (b) extra photons to be emitted by the electrons as they bounce around. The new photons scatter in random directions to be sure, but some of them must make it back into the apparatus, bounce around, and come back to the detector, producing a new pattern. Eventually this will settle down as the electrons and photons lose energy over time, but it happens long enough to produce a pattern.
So I don't really see how the original photon interfered with itself; it appears that multiple photons were generated and recorded, and as energy is lost, these waves overlap differently and produce a pattern.
This is my interpretation and I am glad to say I am wrong if provided with some evidence that shows we can rule this possibility out.