ad. 1) Yes, they can. In the rules for charging "the closest" stand is determined in the way that the priority to be "the closest" is given for the stands that can see and can reach the enemy. So in your case you can see but cannot reach (stand must be ignored) and with the second stand you cannot see but can reach and this stand becomes "the closest" and the one to begin your charge with. Please note that still the closest enemy stand that unit can see will be determined by the distance between your stand which can see and is not nominated to be the closest one and the enemy stand it can see (and cannot reach of course).

ad. 2) As for the second question the answer is rather easy. Let's consider the intensions here. As you are not obliged to maximize edge contact while lapping round in pursue move you are perfectly allowed to place your stand one milimiter closer to your stands attacking from the flank and then there will be no discussion about if the corner is visible or not. So my answer is: discussion if the corner is visible here or not might be conducted but the spirit of the game would be not to see the Chaos Marauders 2.
And according to the rules to see enemy you have to have the possibility to draw uninterrupted line from your front edge to any edge of the enemy stand. And corner is certainly not edge (only the infinitely small part of it).
Hope this might help you.