HOLD UP, let's take a step back here. What exactly is the deal with this Mario Event? Based on what people like Natedrake have said it was meant to be this presentation/possibly live event for the 35th anniversary, including game reveals, DLC, the Universal partnership, possibly talks about the movie, held sometime in April/May. But here's the thing, according the original Venturebeat article that all this Mario 35th stuff like the remakes was first rumored and picked up by basically every single gaming news outlet, this event was originally going to be held at E3.
"The core of the report is that Nintendo originally planned to focus on Mario’s 35th anniversary at E3 (the Electronic Entertainment Expo) in Los Angeles in June. But organizers canceled that event due to the spread of the coronavirus. Nintendo is going ahead with that promotion, and it will likely hold a Direct-style event to provide all of the details. That includes info on remasters, a Paper Mario game, the upcoming Mario film, and Universal Studios Super Nintendo World Theme Park."
https://venturebeat.com/2020/03/30/nintendo-is-making-3d-mario-remasters-for-his-35th-anniversary/
So, whatever was meant to be revealed at this Mario Event that we don't already know about right now was meant to be revealed AT E3, they only planned to do a Mario themed event after that got canned. Let's theorycraft a timeline.
- Original Plan : Spring Direct, revealing Paper Mario+Potentially the Mario Maker Update and announcing the 35th Anniversary, E3 reveals the remasters+3D World+Potentially other games+Non-Game stuff
- Revision One : Splice Spring Direct into a mini and only reveal the bare minimum of what we are releasing this quarter, hold Mario Event in April/May instead and reveal what was meant to be at E3 along with Paper Mario/Mario Maker 2 update
- Revision Two : Mini Direct still happens, but the Mario Event is cancelled, forced to shadowdrop both the MM2 update and Origami King, instead reveal Mario 35th plans at a later date (July 20th?)
Again, whatever was planned to be in the Mario Event was always meant to be revealed at E3, likely part of the conference itself, based on what we know it seems Mario's 35th was meant to be their big thing for E3 this year like how BOTW, Mario Odyssey, and Smash Ultimate were in the past. Here's what would have likely tied into that based on what's floating around.
- 3D World Port
- 3D Mario Remasters
- Non-Game stuff like the themepark
- Potentially MK9 based on what Verge has said?
- Potential Spin-Offs? Still no idea what Camelot is doing at the moment.
Now obviously that does lead into the question, is it farfetched to suggest the idea that Nintendo would also tie in a Mario character being Smash DLC as well? I'd say it's plausible.