Makarov did quite the overkill. Well,he is still missing,and considering no one can contact him,he is probably on the sirius island along with Doranbolt,Laxus and the thunder god tribe hiding lumen historie. I doubt he would have left it behind for someone to find,like the guild's old flag.
No way would Makarov let Doranbolt roam free now that he knows about Lumen historie,so they are probably together. Laxus would certainly never leave his grandfather again,nor would Fried and the others leave Laxus.
Well,next chapter is most likely the election of the seventh guildmaster. Somewhat lame that they aren't waiting for Makarov and the others before choosing the new master,but I suppose it can't be helped. Well,they would certainly agree with their fellows's choice.
If Makarov were here,he would certainly refuse to become guildmaster again,saying it's better off with the next generation. Laxus,who is the favorite candidate,is not here.
Well,if he doesn't appear suddenly next chapter,Natsu will probably become the new master. Either him,or,I don't know,Lucy. They were the ones responsible for fairy tail's rebirth,so they are certainly the strongest candidates.
Also,it's not a matter of strength. The guildmaster doesn't need to be the strongest or the smartest member of the guild. If that were the case,Jura or Kagura would be guildmasters. The master simply needs to embody the guild's beliefs,have charisma and be respected.
Well,it's also not a matter of knowledge. Many leader and businessmen in our history weren't that smart to begin with but they were surrounded by people who were. One way of the other,they knew how to get things done.
Honestly,I vote for Natsu. He was the one who pulled the trigger for fairy tail's revival,for Lucy lacked the courage to do it herself. People say he is too dumb for the job,but he can be impressively smart and perceptive when he wants to be. Plus,technically,he already has experience as a guild master.
Laxus or Erza would be too predictable. Rather unfortunate for Laxus,specially because I like his development. Also,Natsu has more feats here. He played a key role in the downfall of the Ballam alliance and he saved the future from Rogue. Plus,him being the guildmaster would be really symbolic when he finds out about his previous occupation in Tartarus.
Well,after that being decided,they will probably either rebuild the guild building in magnolia or go searching for an empty mansion to work as a replacement.