After looking at this (and your videos) and thinking about it more, I'm not so into using [sigmund~] anymore. Because it only works at message rate, I don't think it's well suited for resynthesis. I think it could be done with FFT, but I can't wrap my head around how to do it with live input (I'm not well-versed in FFT anyway), which is what I think you want to do in the end.
But I think you'll be okay with band-pass filters, unless there's something bigger here your trying to achieve that requires strictly sinusoids. I do have some recommendations, though, for how to improve your patch a bit.
First, I think you should switch to [vcf~]. You can control the center frequency at audio rate, and if you intend on doing any bends, you'll likely want that.
To go along with that, I don't think it's necessary to use _out of [sigmund~]. (In fact, the way you have it now, if your guitar is slightly flat, it will truncate to the half-step below. It should actually be [+ .5]->_if you're looking to "autotune.") Doing that kills some important guitar idiosyncrasies, like bends and vibrato. You might be better off instead using the non-integer MIDI note like this:
| [r partial.number]
Obviously you'd rework that a bit to fit in your patch, but I think you get the idea.
To pull frequencies out instead of isolate them, you'll want a notch filter. This is just a reverse band-pass filter, really, so you could make one like this:
Also keep in mind that [sigmund~]'s output is delayed by the hop size, so you should delay the copy of the input signal going into the filters by that amount if you want the filters to line up perfectly with the notes. Well, it won't be perfectly, but "closer to perfectly."
One last thing, instruments like guitars have noisy attacks, which can result in initial erratic pitches coming out of pitch trackers. There are two things that can help with this. One is to low-pass filter the signal going into [sigmund~] to keep the output from being to high (Some pitch trackers actually work better if you get rid of some unnecessary high-frequency content. Not sure about [sigmund~], though). The other thing is to get a running median of the output of [sigmund~]. This essentially has the effect of throwing out any outliers. You can use [median_n] from mapping to do this. You may find you'll need to delay the signal a bit more for this to be accurate, though. Probably by hopsize*median_n arg/2.
Hope that helps.__