Honestly, the examples I gave aren't even that bad.

A. People interested in TT will easily play 100 matches (NPC or player) over the course of an entire week. Those that aren't interested in TT won't be getting it anyway, but that doesn't mean it shouldn't be included (just look at all the crafting challenges we have, yet there are plenty of people that don't craft at all)
B. GATEs are the same way, honestly. You have a GATE at every time it ends in :15 or :45, so it wouldn't take long to get these either (if you participate in them anyway)
C. I can understand about the mini Cactpot, but there should be something in there for luck. Some people will clear that challenge through one ticket while others will pick it up throughout the week. I guess 5,000 would be more reasonable though.

Lastly, a lot of the stuff will be easily accomplished anyway since there are still a flood of people in the Gold Saucer as it is and those that aren't interested in the Gold Saucer just won't get them (much like the people that never bother gathering or crafting).