I have a more extensive investigation on Meiji Pokémon Lottery Ice Cream stickers here: Sableguy Non-TCG Identifications - #22 by sableguy
However, for the purposes of identifying your items:
#45 - 1998 Meiji Pokémon Original Goods - Sticker
On the back of the sticker that you posted, it has a lottery deadline of October 31st, Heisei 10 (which is October 31st, 1998). From the info linked above, this was from an ice cream box due to its size and dimensions (likely to be a box of ice cream bars), and was possibly produced in 1998, as there are instances of Meiji Ice Cream Bar promotions that concluded earlier in that year.The back of the sticker states that it is from the “Meiji Pokémon Original Goods” campaign in Japanese.
#44 - ???? Meiji Pokémon Ice Get - Sticker
The back of the sticker states that it is from the “Meiji Pokémon Ice Get” campaign in Japanese.
I could not find a year for this sticker.