If they have the Master-Servant link then Akira might start having dreams, I'm sure the school library will suddenly have a book on Holmes available

Why rename the weapon? It already has its own name right? Just think it is a bit weird and unnecessary.

Nice second chapter, I like it. one thing i would like to see Moriartys reactions to Jokers different personas and the Phantom Thieves in general.

The coffin is more then just a machine gun it a rocket launcher and a...beam cannon so it basically versatile in many ways a flail in close combat, machine gun (basically to me it a minigun) in medium range and a Rocket launcher and beam cannon in long range if and his NP Dynamics of an Asteroids is basically an overkill to be honest and in my opinion really good against the reaper

This is... quite intriguing, to be quite honest. Moriarty is a very fun character in FGO - he comes across as a little clumsy and senile, and then wham! his over-the-top plot works out just about perfectly - and he does offer quite the bit of expertise for the completely green Phantom Thieves to fall back on. Then there's the fact that he and Arsene are kind of connected as a consulting detective's former nemeses (disregarding copyright infringement) that makes the pairing all the more interesting. But, if the last thing he remembers is Shinjuku, then Moriarty... doesn't remember his daughter! That is a crime!

I like this idea

Excellent start. Look forward to more.

Nice interactions. Good start n plot so far.

Hmmm the only servants that might be note worthy in this fanfic will be

Of course moriaty since he in here already
Charlotte Corway
Mordred (considering she knight of betrayal and she started a rebellion)
Okada Izou
Edmond Dante (considering both him and Akira are almost similar considering both of them are framed of a crime they never commited)
...well that all I know for now LOL

Well, this has certainly perked my interests, look forward to more.