Help me reproduce this sound --> Midnight Brunch - Midsummer Night

I think this sound is based on 2 detuned sawtooth oscillators, with something like 70 detune amount. Also, The mixing of the oscillators should be a little towards one of the oscillators so the detune effect is lighter. The nasal quality comes from the filters - I would use the two filters serially to bring out only a portion of the mid-high range: high pass filter at ~95 and low pass filter at ~110. Also setting resonance at about 30 for both filters can make the sound more nasal. Now we need to bring back some high end, we can do this with distortion - bring the saturation all the way up and enable hard distortion in the saturation module. You can even add more distortion from the FX1 page, some light distortion with everything except high cut in the ~70% position. You can use a little high cut if you want to tame the sound.
Now the only thing that is missing is the amplitude envelope which is controlled by 2 elements, first is LFO1->filter gain at 80% or more. I can hear in the link you gave that at every key press the sound is a little different in the LFO phase so leave trigger phase at 0, and maybe use mono mode if you want. The timing of the LFO seems to be clocked to 1/6. Secondly, there is a slow amplitude envelope: with attack at 40+ and decay or release (depending on how long you want to keep the note pressed) at 75+.
Finally there are a few things that were made probably in the mixing stage but can be done with the Virus as well - one is high pass filtering on the track using the low EQ of FX1, at minimum gain and relatively high frequency, and some light reverb effect.
Hope this helps.

Ring modulation is a somewhat unpredictable. It usually makes sense when one of the oscillators is a sine wave. Otherwise, it usually produces pitchless noise. Maybe if you want to make your sound scream a little bit...

In the modulation matrix, the filter gain destination is referred to as Osc Volume, there are several other naming inconsistencies in VC as well...
Regarding your other question, no worries, in fact I think that since I joined this forum, you are the first user that posted a link to a song that is actually a part of my daily diet :-). The sound itself is mostly characterized by the vibrato (LFO3 will be useful with its delay), and the fact that a low pass filter with some resonance, closes down very quickly. The oscillator this sound is based on is sawtooth here as well, and the bottom end is taken out the same way I described for your first sound. Instead of reverb we have delay :-).