It does not matter for training which FXCM account is used - it would only matter for testing. I do not know why you could not download 2015 prices. But it's not good to train or test with missing 2015 history files, so make very sure before that you have them. Z12 retraining does not produce a log as to my knowledge. This could be good to add to the next version. But if you want to see the training process, just do a normal training instead of a retraining.