If you are looking in the crash reports folder you are posting a crash report, what you have been asked for is the log, located in the logs folder, for the version of forge in the previous log you will need to post debug.log.
When using the vanilla launcher debug.log is found in .minecraft\logs and should be posted using Pastebin or GitHub Gists,
where possible use the upload button rather than copy-pasting the contents of the file.
One or more of the files in your save is corrupted, you might be able to delete BCMod-Items.dat and have the world work but I'm not sure what it will change.
You need to include the .jar extension when using the java command.
and use CMD, the command does not work in powershell, you can open a cmd prompt in powershell by typing cmd.
Yes. If that is the @Mod annotation from your mod please post your mod's source code in a GitHub repo, be sure to have the "root" of the repo in the same folder as the build script and the .gitignore provided by the Forge MDK.
I recommend you also check out the StopModReposts project and install their browser extension, it will intervene and alert you when you visit a site on their blacklist.
I believe Pastebin and GitHub’s Gist service will allow files larger than direct uploads to the forum, both sites are linked in my signature, I know Pastebin has a limit of 512K, not entirely sure on the Gist max but I believe it is higher.
If you DID go through the official site please note that the links are monetized through adfocus and only the skip ad button in the top right of the adfocus page will get you the Forge download, under that top banner is an ad that Forge has no control over, that part is up to adfocus.