I'll say korean is prolly the easiest to start. Once you memorized the alphabet chart you can read almost every single korean word you see, then go on and learn the words and sentences for daily conversation.
Japanese is okay too. One good thing about Japanese is that if you don't remember the characters, you can always look for romanji alternative. My best suggestion to start on Japanese is to first learn the basics, then when you are ready to learn the hiragana and katagana, look for a japanese song that you like (and has romanji) and train yourself in memorization and pronounciation.
I have no idea how to start Chinese. My brother tried to learn from Duolingo and that sucks. I would recommend watching chinese drama with subtitles, once you know how to speak some chinese (either mandarin or cantonese), advancing to learn individual chinese characters would be easier from that point onward.
