My opinion: It wasn't the same killer. No doubt in my mind.
The Ripper murders bare no resemblance to the Annihilator's "technique". Based on the information we have, when you compare both cases you see that the chances that these crimes were committed by the same killer are very slim. Is it possible for a killer to change his MO/signature ?? Of course. But in this case there's too many differences and not enough similarities, I see no solid connections between the two cases other than the fact both cases happened in the late 1880's.
Even back in 1888 some people tried to link the Ripper murders to the Austin murders. Several newspapers, including the
New York World and the
Irish Times, drew connections between the two unsolved cases but these connections were mostly based on speculation and wishful thinking.
And mademoiselle I respect your opinion but I don't see how you can be positive about "Maurice". Nothing solid links him to both cases, and the theory that he was working on a ship is based on nothing solid and it seems like a lot of the so-called information about this man was created by one or many of the newspapers I mentioned earlier in this post. Like the Ripper case it's sometimes difficult to know what is the truth about the Annihilator, like the Ripper case it seems like there's a lot of myths about this case and not enough facts. I have over 20 Encyclopedia/Almanac about True Crime/Serial Killers, and the informations about this case is often different from one book to another.
If you want to read more about the Annihilator I recommend
The Encyclopedia of Unsolved Crimes, by Michael Newton.