I have a similar problem. I can run with just forge, or run with just Optifine ( the game will run, but Optifine won't load ), but if I run with both Forge and OptiFine, It will crash with this FML log. Here's both a link and spoiler for which one you prefer. https://paste.ee/p/q9Tuc
I've been having a very similar problem, but when I play with only Forge, it works. The only time that I get a problem is when I add OptiFine to the mix. Here is the log file when I launch with Forge and OptiFine. FYI, I launched with Forge first, then I downloaded OptiFine and launched again. https://paste.ee/p/q9Tuc Also, I can launch with just OptiFine, but when I do, OptiFine does not work and none of the settings from it show up, but normal Gameplay goes by as usual. Only when Forge and OptiFine are together do I ever get an error.