About the injuries, try the following:

- Use your red boosters until there is 1 day left, then let the player heal naturally. I really believe that it's the way to go to reverse the injury curse
- If you lack red boosters, sell the player and buy a new one. At this time of the season, I would imagine that the transfer market is quiet on all servers so doing this wouldn't cost you more than 1 or 2 tokens per player.

I feel your pain about the player morale loss. Last time, I used 2 packs to put my GK to "Superb", won a match 7-0, then found out that his morale was back to "Good" right after this match... Maybe his wife told him she wants to divorce after the game....