Nicky, I've only read a few pages of this thread, but I noticed you stated you aren't looking to make a career out of singing. If that's the case, I can't help but wonder why you've spent years worth of time and money on a vocal coach. That's quite an expensive hobby.
First of all, you need to make a concrete decision on what your aspirations are. Is it really just a hobby or are you serious about it? Do you want to be an "ok" singer or a great singer?
If you're wanting to be a great singer, you need to first find a new coach. He/she has failed to help you through just the mere basics, and apparently only gives a shit about taking your money. Secondly, do NOT try to do this on your own with the assistance of Youtube videos. I can't even begin to tell you how many people think they've perfected certain techniques through these videos, but have actually not. It's incredibly easy to get things wrong, and not even know it until you actually try to sing a song, and everything falls apart. You need a qualified professional paying close attention to what you are doing, ready to correct any mistakes you make. Furthermore, the entire process is a hell of a lot more involved than simply going through scales and doing breathing exercises.
Last, but not least, I implore you to put aside any concern for image, stage moves, and making videos for now. It is not where your focus should be right now. I know you probably don't want to hear it, but if you're really serious about this, you need to start this journey over from square one.