About the container shape; I don't it affects the fermentation, but most doughs above a certain hydration level will sag and lose their balled up shape. Solution is to use individual round containers capable of containing the freshly made dough as well as the risen/fermented dough.
The problem with the test you did with the yeast is that you don't have a reference. Yes, your yeast is at least partly viable, but is one teaspoon of your yeast equal to 1 teaspoon of your yeast when you just opened the package it came in?
To test that you could make two identical high hydration 'doughs' and in one put your old yeast, in the other new yeast. Put them both in separate, identical, tall and thin containers and see how fast they rise relative to the other.