In a true foundations class, I would be teaching recall to heels. jumping form, see wood run, contact behavior, forward and lateral sends, cik/cap, body awareness, crosses (though I do agree- a good forward send is needed for a good rear cross.. which is why I did not do many with Aurora until I got a stronger send on her, as she is a dog who will panic if you cross behind her closely). I would start teaching distance, target training, and spend some time making sure dogs had basic obedience skills. I would also be working specific exercises to build drive/motivation.
I do think both crosses on the flat can be taught in foundations. It is on course where it is harder to not first have sends.
I think I would honestly bore many a new person. Most want to jump straight to the fun stuff and skip the real foundation work.
I don't know that I would teach classes the exact same way for true new people as I would for more experienced people. I have found myself working more toward following a lot of what Silvia does on her speed dvd, but I'm not sure it would be the way to start people who don't already know enough to keep it together while at speed. She teaches speed from the get go, but most new people couldn't do the recall to heels, or crosses at speed right away because it is hard enough to figure out what to do with your own body without having to worry about keeping up with a dog, or pushing a dog to go. Most people new to the sport would need it broken down to be able to get through the thought process of what they are doing... I think it could be counterproductive to teach them at speed and have them confused thus confusing their dog. I can remember spending a lot of time 'but which foot should I be turning with?', and I couldn't have done that at speed right away. I would almost have to break up classes for past agility competitors and true newbies with the experienced ones who already know what to do with their body starting more with adding speed right away.
I would want to teach distance to all handlers from the get go as there is plenty that can be done outside of real agility to start teaching distance so that the skills are there when they are needed. You can teach it to puppies with toys and/or food and/or targeting and a cone or other object. I feel distance can be a useful skill for any team. Most of us really can't outrun our dogs, and even with the ones that seem the same speed as the handler, it would often be useful for a handler to be able to get that dog off their side so they can get where they need to be. I also feel distance is a great confidence builder. It is also useful to have when it comes time to start putting courses together. I can think of countless people who complain they can't front cross because their dog is too fast, or because they can't get where they need to be with their dog glued to their side. With distance, that becomes less of an issue.
Of course, I think ANY of the sends and ANY distance can be beneficial to having in conjunction with or before crosses because it makes it much easier to do them successfully. I much prefer a dog I can forward send with for a rear cross as opposed to one who is stuck at my side and I have to do an awkward cross with. I would much rather have a dog I can send out on a pinwheel so I can go ahead and do my front cross as opposed to having to force a cross.
Go on is useful to have as it is nice to have a dog who can go ahead and go on when your motion is continuing forward and you need to take a long straight line of jumps... very common in AKC in novice jumpers.
I'm not sure this is my most coherent post... There are a lot of thoughts here. I'm sure if I sat down and thought about it longer I could come up with plenty more things to work on in a true foundations class.