Greetings fellow Genobros!
The weekend is finally here (at last!). Earlier today, as I was on my way to work, I thought for a moment once again on the CacoMallow leak and Geno. Here's my take on what could potentially end up happening in regards to Geno, and Doom Slayer.
1. In this year's E3 Nintendo Direct, we witnessed the unprecedented collaboration between two direct competitors coming into agreement, and making it possible for a beloved, iconic video game character duo join the Super Smash Bros. Ultimate roster; Banjo & Kazooie. This lovable duo which was developed by Rare, was somewhat of a close relative to the rest of the Nintendo IPs back in the era of the N64. Of course, we then had the purchase of Rare by Microsoft and the bear and bird were taken away by their new foster parent. Fortunately in present day, we've been blessed with Nintendo and Microsoft's good relationship that we were able to witness the aforementioned feat.
Now, in regards to Geno, I'd say he's a character that has gone through a similar experience. Back in the SNES era, Squaresoft (now Square Enix) made quite a number of games for Nintendo, and among them was Super Mario RPG. Within this gem of a game, we met Geno, and from there and onward many have come to cherish this unique character (myself included). Unfortunately, after Nintendo and Squaresoft's fallout during the transition of console generations, Squaresoft sided with Sony to expand upon their IPs on the Playstation. Geno was never to be seen again... that is... until we got re-releases of SMRPG on Virtual consoles. With Square Enix now seemingly being in better terms with Nintendo (most notably after Cloud's inclusion in Smash 4), I sense that Square Enix may follow suit (similar to Microsoft and Rare), and allow for Geno to join Ultimate's roster. I see this similarity as a good point in favor to his chances.
2. I've come to accept that, both Geno and Doom Slayer, may be revealed and released around the first quarter of 2020 (say around March). My reasoning for this is because on March 20th, 2020, DOOM Eternal, and DOOM 64 will launch on the Nintendo Switch. What better way to promote the DOOM franchise, along with its latest installment, than revealing/releasing the Doom Slayer for SSBU near that date? Likewise, March being the month of SMRPG's anniversary (going by the release date in Japan), I also believe that the imminent announcement and release of SMRPG for the SNES library on the Switch beckons the reveal of Geno as a playable fighter in Smash. I've seen some mention Geno being more suitable for an E3 release and, I do agree that it would be a fitting time as well, however the date of SMRPG's anniversary is also a possibility. As for Doom Slayer, I'm banking on him being revealed... as a matter of fact, either at the same time as Fighter #5 is revealed sometime in January, or after Fighter #5 is released. To me, the CacoMallow leak is legit.
These are my humble and honest opinions on the matter.