if youre wanting to have say 2 or 3 side by side videos of you playing different parts.

Just using each videos audio will be easiest.   youll have to sync all if them though.  You could either stay quiet for several seconds prior to recording and then play the violin parts.  Once you have it inside of some type of video editor and all the tracks imported...just line up the audio track waveforms.  youll have to adjust them and watch a few times to see if all the videos are in sync. 

Youll have to work through how to import and place on a timeline first.   so maybe initially to make learning the software easier.. take 3 videos of yourself speaking the same written sentence so you dont have to worry about playing.   or clap loudly 3 or 4 times.   practiceimporting and lining those up on timelines.

its another one of those things to just try.   your laptop probably came preloaded with some video editor.  experiment with that first.   I use davinci resolve but if youve not did multitrack videos it may take a bit to get familiar.  I think its the best all in one editor but theres plenty of great alternatives.

whatever you chose if it works it works...a phone app or a desktop.  use and learn it as best you can.

if just playing along to a backing..play the backing over a bluetooth speaker and record ypurself playing to that.ypu may have to do it a couple of times and move the speaker so the camera mic hears it and your playing.

theres no need to split up the audio from video with the scenerio you posted.  itll be easier and just as good to keep the audio/video together.

The pro vs con queation...theres no real pro or con to either.  it depends on what youre wanting to do.  each way has quirks to work out which to me are fun to work through.

give either one a try and whatever youre stuck on maybe post a question about.  

when you record a video..audio is attached..its part of the video... when you import it into davinci the audio comes with it.   its one file.  But theres audio information in that file and video information in that file that gets seperated to a video track and an audio track once you drop it on the timeline.   if you imported 3 videos and dropped them on the timeline..youd have 3 audio tracks and 3 video tracks.   now you can delete either portion seperately if needed.  

i import my videos of landscape ...my pictures ..whatever and drop on the video tracks.   The multitracked audio files from presonus i import and drop on one audio track.  its the backing of the video.  1 or more video tracks with 1 aufio track i did in presonus.

since i multitrack the audio with different parts. that method is easiest for me.. if i wanted a 1 man band type video of me playing different parts in different windows...id just use the videos and sync them up.

different goals same processes in the end.  

if you record with effects active theyre embedded in whats recorded.  So youve put that step up front.  so you can bypass any audio mixing and just adjust volume levels in the video software.

lots of jibberish..🙂   maybe helps.

if you use 2 different cameras to record ONE performance, you can use multicam in davinci to get those music video kind of cuts to different perspectives.  This is something you may wanna try.  the camera settings all have be the same...i.e. same frame rate, size etc...  not ever done this but its available