No. Mooshrooms are still in 1.3 and onwards.
No your have to wait for the mods to update which may take some time.
I few seconds plus or minus, depending on how fast your computer is. (this does not count for the actual time it takes for minecraft to open, just for it to load, this also does not count if there is an update, then it will take as long as it would for it to update.)
Nobody knows. Be patient, 1.6 can take a while.
It depends on the person who made the mod. some modders will get right on it to update it but some are lazy and may never update it.
Currently, the Xbox 360 version of Minecraft is running 1.6.6 beta. This update came out before the adventure update of 1.8. It will take a while for the Xbox 360 version of Minecraft to catch up to the PC version of the game.
Usually no, most will either crash Minecraft or will not work. You have to wait for the Mod maker to update to the latest version of Minecraft unless they say other wise. It may take a few hours or a few weeks to update mods.
No, but you need java Edit by Ozaicanyousee. If you ever have a java update, take it! If you do, Minecraft will have a lower chance of lagging and more advanced graphic sometimes
by killing a cow, but not all cows drop leather. it may take a couple of cows to get one piece of leather
In order to have villages they would have to update minecraft pe and it would probably take up too much space on your iphone/android.
Anywhere between 5 minutes and 5 seconds depending on your internet speed, but they do not generally take more than 1 minute to update and updated are few and far between.
Most will not work in a newer Minecraft update with out being updated itself. You would have to ask the maker of the mod you have now. Only they will know. Every mod is different. Depending on the mod it could just take a day or so or weeks to update the mod so have patience.
Once you open minecraft, click "options" then click "Force Update". Then it will work, but the first time will take awhile.