The second link stone is outside the Yureyu building, and I'm quite sure there were no additional stickers added (though you can supposedly obtain a bonus sticker thru a glitch). Bulba is in that house Azurine Island (needs 5 badges), Tepig is in Pyrous Mountain (needs Strength and u gotta chase him around), Mudkip is in the wastelands in the rain (u needa talk so a man in Obsidia? In clear weather I believe). Riolu is obtained from trading with the girl on the roof of the Apophyll Academy (I can't remember what Pokemon she wanted in return but i think she tells you). Lastly, Eevee is in the Mysidia Rail Cave (Hint: look at the rocks)
Tl:dr, it's tedious.