It's cute. I really like it. I feel like the homage to the videos has to do with the song itself, since the title is loosely translated to "The Dream's Welcome Ring Ring" (...or something like that?). So maybe she's including the videos cuz they're a part of her dreams coming true, although I wonder why she included those two specifically. PONPONPON obviously was her debut, but does Fashion Monster have any significance? Was it one of her more popular ones? (I wanna say it was but I don't wanna say things without actually knowing)
Actually she's refering to all her singles released so far. There is a CANDY CANDY reference @ 1:00, Mottai Night Land, Furoshiden, Ninjarebanban @ 1:53, I just can't find Tsukema Tsukeru and Invader Invader bit I'm sure it's included as well.
I think she's "looking back" (retroperspective) to her music career so far. She's leaving it all behind and is moving on to her next chapter, but still it's sad for her to leave it all behind, when you know it never will be the same again. It's like watching the music career of Kyary growing up. Ponponpon and Fashion Monster are just her biggest hits and most memorable songs so far from her (in my opinion). I really love the video, have to say it's my favorite music video from Kyary because it's still in the style of her but more normal, she looks so freakin gorgeous and natural in the video, never have seen her so beautiful before!
/edit Oh and I just found at that Fashion Monster is her favorite song, so it got a special treatment in the video.
/edit 2 Just found Tsukema Tsukeru, it's also included in the circle @1:00, it's the first, the eye with the fake eyelash (followed by the onion from CANDYCANDY, the "20" for Furosidation, the dancing Ninja for Ninjarebanban and the strange head for Mottai Night Land..)