Hi Jeff,
Thank you for writing in to us.
Firstly, kudos to you for choosing to foster! Beagles are very intelligent dogs and this intelligence bring with it both good and bad character traits. They are certainly easier to train on the whole but tend to get self-absorbed easily becoming disobedient. Thus, ensuring there are set boundaries from day one is key to successful training (I am glad that you wrote in to us on day one!).
You definitely have the right ideas in mind when it comes to correcting problem behaviors. I suggest you have a read through the obedience training section in the Secrets to Dog Training ebook and also the alpha training bonus book. Start the obedience training regime and enforce basic alpha training methods to show him that you are boss. If he doesn't listen to 'NO', have a squirt gun handy and give him a good squirt of cold water right between the eyes. Do not like him play-bite, even if he is being gentle! I don't feel the destruction of his crate and marking are signs of pre-aggression. Being newly fostered is very stressful and it could just be anxiety behind these actions. I feel that if you exercise him thoroughly in the morning and in the evening these problem behaviours will soon decline. Take him on frequent doggie play dates (the best way to exercise a dog and get them to learn good doggie manners) and also make sure he interacts with people frequently too. If he is left alone things like having music/the radio turned on may help keep him calm and chew toys will help save furniture,shoes etc. from being destroyed.
I unfortunately cannot give you a deadline to help with your final decision. Some dogs settle quickly, others take their time to adapt. I think that if you have faith in him, love him unconditionally and devote at least an hour daily to exercise and train him, you will soon have a doting, obedient and faithful companion!
Good luck with training, I hope things work out well. Do keep us posted on your progress and feel free to write in to us again if you have any other questions.
Regards,
Preethi