A:Answer Short answer: yes.
Long answer. This is directly from Nintendo's website: "Go ahead and share games! Nintendo 3DS games will work on multiple systems, including New Nintendo 3DS XL, Nintendo 3DS, New Nintendo 2DS XL, and Nintendo 2DS. You can also play games from older systems like Nintendo DS and Nintendo DSi, so it’s easy to upgrade to a new system without losing your game library."
For Mario Party Top 100 there is only one difference besides the fact that the 2DS doesn't have a 3D mode. The 2DS has slightly longer load and save times, however I doubt you would ever notice unless you are playing right next to someone who has the New 3DS or New 2DS and you have the (I guess, not *new*) 3DS or 2DS.
