Re: How do you get the following challenges?
The Weekly Challenge is exactly what you described. You need to be playing the weekly challenge which is currently the support classes (sunflower, rose/scientist, engineer) and kill players while they are in the marked areas. It took me several games to get this since all the traffic is focused on that one area so it’s difficult to get in there sometimes. Keep playing, you’ll get it.
The Daily Challenge is done in the mode your playing, Graveyard/Garden Ops but has to be completed by an assault class character. I believe from the peashooter to snap dragon is all assault classes and the first 5 from left to right on the zombie side (sorry, couldn’t remember the order off the top of my head). After you win an ops with an assault character, you’ll earn the daily. Hope this helps!