The reason of smells in sweating problem is the becteria. The becteria present on your skin may be the cause of smell. Wash your body regulary and choose a right deodorant for you. Try to avoid spicy food. For dry mouth its good to consult with your doctor. They will give you right solution for this problem.
Are you on any NSAIDS like Ibuprofen, or other medications? Many meds have the side effect of sweating and that can dry you out as well because of the increased sweating. Also, since you're always having a dry mouth in the winter, I'm wondering if you mouth breath due to sinus issues? I do that as well and have the same issue with drinking water and it seeming to dry me out moreso, and mine is caused from sinus issues. Even though it does seem to dry you out more, please continue drinking the water to compensate for the loss of your body fluids and to stay hydrated. I would definitely make an appt to see your PCP though, as that can only help you! Good Luck!
If you can, I'd see a primary care doctor. The always thirsty can be something possibly. You can also get a mouth wash called Biotene that helps with dry mouth. Dry mouth can cause dental issues so it's good to get this under control. Maybe they can test your blood to see how your kidneys and liver, and a diabetes test, so maybe get a routine physical and have them cover everything. I would have more expected this in summer then winter, so I'm not sure as I'm not a doctor, but good luck! Maybe try a different deodorant too.
Make sure that you wash regularly and properly and use a deodorant.
Sometimes bad smells on the body can be a reaction to the different perfumes and detergents; if you do not empty your bowels on a regular basis and also from eating strongly spiced foods, onion and garlic.
As you have a constant thirst, it would be a good idea to make an appointment to see your doctor to get checked out for diabetes. Thirst is one of the symptoms of this disease so it is worth getting checked out.
Your doctor may refer you to do a glucose test or may take a blood test to check your HBA1C blood sugar levels.
Another reason for being thirsty can also depend if you eat a lot of salty foods.