So, here's what I came up with in my infinite boredom during philosophy class(you wouldn't believe how easy it is for me to just drift off into wonderland when the teacher starts talking about "being" and "not being" lol):
1-This one I got interested in the most, seeing as Magi is centered around kingdom building and conflicts between factions and ideologies, sending just 1 servant or Shirou can hardly make a substantial change in the world without some major coincidence, not that it is a problem,I'm just saying that the addition of a faction, preferably a team of servants(with enough members, excluding the leader of the group, to match Sindria's generals), like say perhaps the Knights of the Round Table, lead by proto Arthur or Arturia(I believe that these guys are the best for Magi) with Merlin as the "Magi", OR the seven servants of Fate stay night brought by Magi's Solomon to lead the world to prosperity.
2-This one is for all of you Chaldea Fans out there, you can just add the world-saving organization to the Magi world, but I recommend not making Magi a singularity, it would also be super interesting to see how the Djinns would react to Romani(Spoiler Alert: Romani is King Solomon after all, it would be super cool to see him care for Aladdin in the place of his Magi counterpart),one or two BEASTs should be a great enemy for the world if everyone joins together, or maybe Morgan or even Angra Mainyu teaming up with Al-Thamen.
By establishing the kingdom, the main cast would automatically be drawn to it sooner or later, as for the point in time of their arrival, I suggest it would be a period before Alladin arrives, one that is enough for them to be Influential enough to attract the attention of the major nations while remaining completely mysterious to them and perhaps play a role in solving the Balbadd Crisis, the Noble Phantasms like Avalon should be able to protect their kingdom from being spied upon by Al-Thamen, and them being, well, LEGENDARY Heroic spirits given physical form should we follow the Team of servants idea, or even regular servants if we go with Chaldea, could easily contend with the power of Magis and Metal Vessels.
3- If the 1st and 2nd ideas don't interest you enough, then I would suggest Sending the main guns of the Emiya family to sort the mess of that world: I'm talking about EMIYA(preferably post UBW), EMIYA alter( preferably one that had reached max ascension and max bond with the master, returning to a somewhat salvageable Shirou), Kiritsugu Emiya( post 4th HGW or max bond Assassin EMIYA), Irisviel(Caster), Ilyasviel(preferably with Berserker, my boy Heracles doesn't seem to get the screentime he deserves, plus they would need a lot of power to convince the powers in the world of Magi how serious they are, you can even use Heracles Archer from Fate/strange Fake,this is mainly my own preference and is in no way, shape or form necessary, as is anything I propose other than the general gist of things), and MAYBE Maiya, Sindbad being the main villain is reasonable if they are the only ones to be brought.
Well,quite frankly,I'm not just going to offer the idea like that and sit lazily waiting for someone to work their a**es off, but going at it alone would doom both me and the ideas themselves with my poor skills,so should anyone be interested but need help, I'm willing to provide any help I can at all times, feel free to PM me anytime.
The ONE condition I would like to stress out is to PLEASE not mention the "outer gods" in the fic because that part is just completely worthless even in canon, it's completely unnecessary and they don't even do ANYTHING of importance in canon.
OR as the kind ENDDRAGON369 suggested, we could have Aladdin go to Chaldea instead, it would be worth it to see how he changes things: his bonds with the servants, especially Romani/Solomon, his clash with Goetia, using Solomon's wisdom in Singularity 6 and when the Wolf dies in Shinjuku and other moments like such.
Well, this is is for me, this is Roxas logging out.
Have a nice day!