Mike,
I'll try not to overwhelm you with too much detail.
I am a Weimaraner breeder in the UK and also hunt over my dogs. I also run a forum for people who work their HPR's (what we call them in Europe, I think in the US you refer to them either as versatiles or bird dogs?)
Firstly Male Weimaraner aggression, unfortunately as the dogs were bred for a couple hundred years as guard dogs as well as hunting companions they certainly can become very territorial esp. from 8months to about 2 yo when testosterone levels are at their highest but IF you put the correct training and effort in your dog WILL come good (my boy is a couple days short of his second birthday and is turning into a lovely companion) The Weimaraner was one of the three breeds used in the foundation stock of the Doberman Pincher. Aggresive behaviour in the @$$$@ (toward humans) is much less common. You have to remember that even now to breed from a Weimaraner in Germany it has to pass a test for man "sharpness" and cat "sharpness".
Secondly bloat. Their is an awful lot of mis information / disinformation put out about bloat. One of the US universities has produced a lot of good information about bloat and the causes of bloat.
http://www.vet.purdue.edu/epi/bloat.htmYes the type of feed your dog has can influence the likelihood of bloat, stress has an effect, one of the biggest effects is the speed the dog eats at (so you can put a stone in the feed, chuck the feed out on the grass and let her eat. Basically anything to slow her down) Don't feed her from raised bowls as the dramatically increases the risk of bloat.
Hope I haven't banged on for too long and some of the info is useful!
All the best with your pup and enjoy her growning up, it doesn't last long :)
Regards,
Mike