Grryfindore, the game's stages do not change each day. I believe the second stage starts on the 4th day, then the 6th for the third.
The hunting job was indeed bugged so that's why it was giving 10% on the rewards instead of 100%. It has been fixed on the server now, even if the client still Says 10%. The arrows require iron, but you do get 5 arrows for 1 iron bar. When it comes to things like leather armor, I don't believe it would require too much iron. There are ways to get iron that don't require arrows (cows for example), but even if a player relies only on hunting they will spend an average of 1 arrow per hunting trip. So you'd get 5 furs for 1 iron bar. Each plot has an absolute minimum of 5 iron ore tiles (almost always more), and each of those tiles will be either 2 or 3 ore once mined, if the player never gets any fast enough to get the "newly discovered" +1 ore bonus on any. That comes out to about 12 iron bars for the plot, minimum. Most plots will likely be triple or quadruple that amount.
If you do find yourself on a plot with very little iron, then I'd recommend sourcing leather from methods other than hunting trips.
The water tiles have a use from the beginning. Fishing is broken up into multiple jobs, ranging from simple spear fishing (needs a stick) all the way up to using a fishing boat. They are a source of endless food that relies only on your number of available workers and equipment, whereas food sources like apples and bee hives only mature at a certain rate that you cannot control no matter how many free workers you have. In a lot of situations, players would rather have water over the other 2 starting food sources.
The minimum number of trees for a plot is 12, which was carefully chosen to make sure players can get on their feet before running low and being forced to start planning their future accordingly. The game does use randomization when it creates new plots of land, but it is very controlled randomization. What I mean is, each random value has a weighted range chosen so that players should always have enough minimum supplies to establish themselves. It is always possible for a player to screw themselves over with some poor choices early on, like lets imagine a player who chops down every tree and cuts them into firewood, but I don't consider those situations to be game-balance related.
Glad you're addicted man, haha. Game devs sometimes sound like drug dealers.