For the cylindrical cut, just position a cylinder and use a boolean or solid/axis drill. For the modo document, go for it. I've got something similar (see signature) but it's a bit out of date and mostly regarding essential scripts rather than modo functionality. If you'd like I could add you to the editing list, I'd just…
I will try to help some. 1-Not sure what you meant by this...You mean having snapping functionality on while the Edge Extend tool is active? 2-"P" for create polygon. In 901, you can go use Fill Quads too. The Bridge tool also fills gaps very well, as long as you make your selection in a way that Modo can interpolate the…