You'll probably want to use the most powerful magnets you can find. Nd-Fe-Bo are powerful as are Samarium Cobalt if you need higher temperature. There may be cheaper magnets you can use if high temperature is not an issue. A magnet company can advise you based on your temperature...
I am assuming that the flange is permanantly attached to the pipe in real life. If so, why not bevel the end of the pipe at the proper angle and show the flange as a revolved boss attached to the end of the pipe. This eliminated the need for a mate. If you must have a mate, use the planes...
I used Pro/E back in the UNIX days '96. The user interface was horrible unless you like menu's nested 10 deep. I was unable learn to do even simple things without factory training. After a week of factory training I could do simple things and after using it for a year I still didn't feel...
Since you have used hatching in AutoCAD in the past, why not just use hatching to represent the wire mesh on the SW drawing and not worry about it on the solid model? SW has quite a few hatch patterns and there is probably one that would at least be good enough to get the point across.