Sorry to hear that you have these issues.
The counter for the Colosseum goals reset with each goal, while the counter in the Colosseum shows your total whistles. There is a first goal requiring 50 whistles, you will start the next goal with 0/75. I believe you are on the 2nd goal with 87 total whistles and 37/75 for current goal progress. Hope this clarifies.
Try not to exit the game too fast after your last action to allow it to save your progress, especially an important activity. Always do a force save to save your progress on the Storm8 servers by visiting another forest, return back to your own forest and then force shut your game after a minute.
Issue 2 and 4.
Fantasy Forest has lots of animations in the game, some older devices may not be able to run it as well as preferred. Try the suggestions under Device Performance section in What can I do to try to resolve my game issues?. Alternatively, you can reach out to Support: support form for the Agent to do one to one investigations.