So, I went straight to the horse's mouth and asked the developer to satiate some of my inquiries, I'll post his response here in case it interests anyone else:
Q: Is Melda's spear Luna's last weapon or is there a better one? She's the only character where her last weapon slot is still open.
A: Yes, Melda's spear is her last weapon. That last open slot was used for a debugging weapon and he forgot to erase it.
Q: What does the Pentagram equipment do? The description just says "???" and I couldn't figure out on my own.
A: It has two effects - When the "Ray Pentagram" skill is used it unleashes an extremely powerful one-time-only attack called "Gamma Ray" and it also increases damage done by the normal skill.
Q: Is there any (big) event to be triggered in the Mansion with Rahad's sick daughter(Irisha)?
A: Nope, only a very minor one. After the event in the underground slave market and Rahad's death, visit the mansion to find out she's his daughter.
Q: Where do I find the Snack 3 recipe?
A: It's a random drop from the "Man who lost a bet" in the "Dawn Sheppard Bar". Keep giving him money until he wins and he will eventually give you the recipe.
Q: I think the Yaqut equipment is bugged. If I'm interpreting correctly, it's supposed to reduce MP consumption by -1 of whatever skill is put on the first shortcut, but it doesn't do that at all.
A: Confirmed bug, will be patched out.
