Yes, I meant 208v. I'll have to confirm tomorrow with the city, but I believer the service is 240v. The distance is roughly 100 feet from service panel to the oven.

The transformer should be in an accessible location. There should be a switch between the 120V line and the transformer. You really don't want to have the transformer being fed electricity all the time. Using the transformer as a junction box is not the best idea. In other words, probably no.

I don't know where you heard it but that is not true. The current carrying conductors must be the same size. What you might be misunderstanding that in some cases the EQUIPMENT GROUNDING conductor (i.e., the safety ground not the return from the motor) can be a smaller size. For 15 and 20A circuits however, it still has to be 14 and 12G respectively. It's only when you get up to larger sized circuits that it is possible that it is legally smaller. The number of pumps you can put on a circuit is not regulated. It's determined by the load (amps drawn/size of the motors) and the nature of their operation. etc... You'll need to give us much more description as to what you're trying to do to give an answer on that one.

International Standards won't be found for free. There are online web stores from the standards bodies in various country selling them or you can buy a paper copy from the same sources.