Leaderboard

You are trying to install 2 versions of Optifine, one for 1.7.10. Also, next time: don't post screenshots of the error log. Just copy the text either put it in a spoiler or host it on Pastebin or a Github gist and leave the link here.

Either we are in a paradox, or one of your statements are incorrect. I do not believe anyone here will simply make a mod for you, at least not for free. I believe Diesieben07 has stated a few times that he charges an hourly salary of 50$. The other's, I'm not sure about. This place is a forum to learn how to do things, or ask for help. Requesting someone do everything, isn't asking for help, it's asking them to do everything. However, I can tell you key points of interest: 1) Use either a Tickhandler, or subscribe to the LivingUpdateEvent 2) set sneaking with Entity::setSneaking(bool) 3) Key-presses (like pressing F12) only happen Client-Side, so you might be required to use packets to send the updated sneaking to the server ("so that the trees know that you are sneaking")

You shouldn't be using or implementing IInventory or storing ItemStacks in arrays, create an IItemHandler field for each of the TileEntity's inventories and expose them using the Capability system. If you just need a temporary collection of ItemStacks without a formal inventory, use a NonNullList (created by calling NonNullList#withSize with ItemStack.EMPTY as the second argument) instead of an array. This will help to eliminate any potential null ItemStacks.