None at all. That can happen in D3 because there's no human managers in D4 to replace them. Never in D2.
I don't have a trainee so no harm done there. Game shape is a different matter as my players don't usually play 36 minutes, but since its not an exact science, we'll never know if the walkover has an effect.
Its possible you might be able to hang on to your trainees and Congshan. I can certainly understand why you want to keep them. I'm not sure what your income will be next season. Your best bet would be to look at a few D3s and see how much salary typical (human) teams carry, and see if you can still afford them.
And of course, you'll need to look at your prices.