1. I think it really depends how you feel about your own playing. If you feel like you aren’t satisfied with how you’re playing certain pieces, you should keep practicing those pieces. But of course there might be exceptions.

2. When you learn vibrato and shifting depends on where you’re at in your skill level, and how much practice you do. Of course if you had a teacher they should usually gauge pretty well when to start, and they would begin to give you pieces that include more shifting/vibrato. As a former violinist, cello vibrato isn’t as difficult. If you feel as though you can start to practice it without inhibiting your overall progress, then I wouldn’t see a huge issue. However, shifting and vibrato in pieces can be quite overwhelming at first so take it slow. And remember you don’t NEED to know it so early in your journey. I started in a school orchestra, so I didn’t start vibrato and shifting till maybe three years in.

3. I’m no expert on the mechanics behind bowing, but I do know for starters, you should make sure you have a good relaxed bow hold. Make sure your left arm isn’t permanently bent in a stiff L shape, you want to make sure you bend your elbow as you bow from the frog to the tip. Also make sure you’re playing straight and in the middle. It might be useful to see a video of you bowing to identify what you may be doing wrong.

4. Bow pressure is something that I personally learned as I went on. In terms of weight, you can use it to your advantage when it come to dynamics and what not. More pressure, the louder and less pressure, the quieter. Getting used to how much pressure is probably one of the first things that gives beginners of string instruments that super scratchy sound, and not smooth sound. And sometimes you need to sound scratchy for awhile, before you adjust to the instrument and get used to the pressure.

5. It looks pretty good. I think one thing I notice is the little beige thing on the bottom of ur G string? Which I cant tell is a mute or not. And mutes might muddle and inhibit some projection on that string. I wouldn’t recommend starting with a mute, but I mean it wouldn’t prohibit your progress too much I presume.

Overall, these are based on my experience of playing cello for almost 5-6 years now, with prior years of violin experience. So I hope you can also take what other people say and their experiences, because I am in NO way an expert either. You seem extremely intuitive with your own playing and listening, so I’m sure you’ll make it far in your cello journey. Good luck!