Hi Karim. I was playing around with your first question and found a reliable way:
If I use the “PointsOn” command and then use a crossing window, it works.
I found that the wall behavior was quite a bit different than other objects. I won’t get into it here but some of the other stuff I tried wasn’t working. I did some really cool stuff with vaWalls including having an air gap. I found that there was too many things I couldn’t do, so I (kind of) don’t use vaWalls… for now. I model my walls with Rhino. That solves a lot of your issues but it also means more manual work.
Documentation for both Rhino and VARQ is a little behind. Relying on YouTube sucks because you get a lot of old videos. The best resource for learning VARQ is their (free) online course:
I would argue that videos aren’t a replacement for proper documentation… the videos themselves are really good but I HATE having to sift through an hour long video just to find one thing. Maybe we can make a community project or something to fix that.
Do a quick forum search you’ll find it. I’m not using it because I don’t have time 
. Both Rhino 8 and Visual ARQ 3 look really good.
This post might be helpful in that regards. Nothing is quite as detailed as what you’re looking for however:
Google image searches are saving me on a lot of terminology. I think it’s similar between the languages but the fact that I’m not an architect 
One thing to keep in mind is that you can model things very fast in Rhino. That’s really the advantage in my opinion. Even in Revit for example, the parametric families are very quick… until they aren’t… as soon as you need to manually model something, everything breaks down. Don’t be afraid to model things manually. Not everything has to be parametric.