Hey, guys! Z-Meister here! I'm still working on the Muscular Maidens side stories (Levy's Glorious Glutes and Mira and Erza's Titanic Triceps respectfully).
As for the main story, I've made a poll on my profile page for which girls get buff and join Natsu's harem. It's going to be at maximum five (including Lucy and Juvia). The three girls with the highest number of votes join the harem. The choices are as follows
1. Lisanna
2. Cana
3. Ultear
4. Meredy
5. Milliana
6. Yukino
7. Minerva
8. Cosmos
9. Sue
Thanks for your support and have a great day!