Hi Ripton,

(I realize that you are working on viola and my recommendation does center on a fiddle/violin source, but I still believe that this may really work well for you on so many levels.)

I highly recommend the FiddleHed (yes, funky spelling is correct) website with instructor Jason. It is an amazing, vibrant learning environment, self-paced, offering a vast array of solid, quality music education.  Jason offers recorded video lessons, but he also runs regular, live-streamed, real time sessions on Zoom:  group lessons, question and answer sessions, and hang out and play with others sessions.  Lesson and Q&A sessions are recorded and available to view later, as well.  The live sessions add a dynamic level of real, engaging, human community so it’s not just a video archive.  

Right now, Jason’s group lessons are focusing on chords, double stops and playing backup.  This, plus his video lessons cover the topics you list.  Notes are notes, chords are chords, you could certainly adapt this to viola.  There are also play along backing tracks that make practice so much fun.

Many lessons teach how to play fiddle tunes.  However, Jason teaches a wealth of lessons on technique, tone-building, music theory, chord building, double stops, playing backup with chords, improvisation, modes, bowing technique and textures, ear training, etc.  The tunes are interspersed and gauged with the technique lessons and geared to develop skills progressively.  You can follow the programs or pick and choose.

It is not just a beginner program.  There is plenty there for progressing musicians.  Many members are accomplished classical musicians who now want to learn to fiddle.

Jason is a classically trained violist and violinist, a professional gypsy-fiddle-rock-indie band member, a real life music instructor (for decades), and an incredible teacher. (I have two inspiring violin heroes right now: Fiddlerman Pierre and FiddleHed Jason.😊)

He offers a two-week free trial membership.  Why don’t you check it out, it might do the trick?

I’m gushing, I know.  But I love this site. It has helped me improve my violin technique for all genres of music, and it has helped me grow so much as a musician on all of my instruments.  Maybe I’ll see you in a backup chord lesson!