The concern about seasonal flu vaccine predisposing to H1N1 was based on Canadian data that was a) never made public (or at least not last time I checked) and b) not in line with any other country's data. I don't know how their conclusion was reached, but if they looked retrospectively, then it makes sense that those who have had seasonal flu shots last year (ie: those who tend to be at high risk of flu illness and therefore got vaccinated) are the same people who would be at risk of H1N1. Just saying, so that if you want to get the seasonal flu shot out of the way while it's still available, you could. Only caveat is getting the live (intranasal) seasonal flu vaccine if you want to get the live h1n1 too - they have to be separated by a few weeks (sounds like your kids probably couldn't get those given respiratory issues anyhow).
Oh - and the US has a lower supply partly because they chose not to use vaccines with adjuvants, unlike Canada.