My initial thoughts, at first I saw a couple things that I wouldn't call red flags but definitely some things that would have concerned me and probably made me avoid the rescue.... BUT, seeing you being disciplined and making him eat more of variety is no small feat in my book. Also, him keeping the Angel's at bay is also positive to me (full grown angels? ).
Keep at it... but also post pics of him once a month because it will help you see weight gain over time (it will "creep" IF he gains weight (IME)