I think you're making some bad assumptions here.

Common knowledge, like common sense, isn't actually common. Most players aren't after min/max optimization and so aren't searching for tips/tricks. They usually approach content based on convenience or impulse, and sometimes even superstition ("12 is my lucky number so I want my plot to be in ward 12").

Entries will not end up evenly divided between the same plot in different wards (larges will probably be an exception due to scarcity) because of what I said about convenience, impulse and superstition. Subdivisions get far less attention than the main wards since players are dumped in the main wards on entry (the main ward is convenient - the subdivision is not). There are also FCs that are "friends" and will likely want to get their plots in the same ward so will put all their entries into the chosen ward.

Your own numbers show that FC entry splitting for the same plot across multiple wards FCs doesn't create a statistically significant improvement to chances of winning so why suggest it? FCs are going to be better off having one or two entries on small plots with no or low entry counts (back up for the sake of at least getting any house at all) then putting the rest of their entries on a single desired plot with the lowest entry count as close to the end of the lottery period as possible.

I agree that waiting as long as possible to place entries is a good idea with one exception, but I don't agree about the exception. A FC with one billion gil would still only have 20-25 entries for a large. That's not a huge amount when there are only 144 larges total, at least half of those are going to be in individual wards, and it's really not that hard to get 40-50 million gil (FCs are already reliant on member donations when they don't have a house, I could fund several 50 million gil entries by myself knowing I'd get the gil back on either all or all but one). It might be a deterrent at the beginning of the lottery period but won't be for long.

On the other hand, a FC that's desperate for any house at all is going to have a better chance by finding a small in a bad location and dumping all but one of their entries on it at the start of the lottery period. Immediately seeing a large number of entries on a bad small will send other buyers off to different plots that have no or low bid counts. The reserved entry can be saved for the end of the lottery period in case others do start bidding on the bad plot and another plot can be found with no or only one bidder.