It’s more likely than we think.
Seriously though, Isaac has a high chance to be in this Pass with all thats been happening so far:
•Takahashi Bros finish their development time of Aces in Dec 2017 to work on their next project.
•Brand new GS Trademark applied in Sept 2018.
•From having only two songs (Felix Battle Remix from Brawl and a rip of Weyard from Dark Dawn) in Smash 4 for Golden Sun to a surprising amount of added GS content in Ultimate (AT Isaac’s return revamped, Mii Isaac, 8 Spirits with all classes and Adult Isaac being one of the best spirits, Isaac Icon) but no new music despite all that.
-Note: Motoi Sakuraba composed GS music and was composing music for Smash, but was never asked to add at least one GS song? That’s very weird when you think about it.
•ARMS and Golden Sun are the only two Nintendo IPs to have a lot of content, (AT, Mii, Spirits, Icon), but not get (new) music in the base game. Plus no fighter and stage. DLC says it adds a Fighter, Stage and music. Hmm?
•The disappointment of AT Isaac’s reveal completely shocked Nintendo. Has been confirmed by several people on this. If Nintendo didn’t know Isaac’s demand before, they definitely know now!
•Golden Sunday events and our letters to Nintendo at the end of January 2019 of our demand for Golden Sun’s return and having Isaac in Smash.
•Second Fighter’s Pass decided around Summer 2019. Nintendo approaches Sakurai what characters they want to have added.
•Sakurai has confirmed to know games ahead of time before being announced to make characters. FE: Three Houses is a great example of this for Byleth. Could he have seen the GS HD game already?
•The new GS Trademark is finally approved and finalized in March 2020.
•Dark Dawn gets a Trademark renewal this year. However, we recently discovered that it also got a BRAND NEW Trademark this month. Dark Dawn HD also incoming!
•Min Min from ARMS is added and proves that upgrades are possible. Also finishes giving missing content of a Fighter/Stage/Music to ARMS. Something that Golden Sun lacks too. Could GS get the same treatment?
•At this point, Sakurai must have seen GS HD by now. Isaac (or possibly a different GS character?) can easily be used to promote the new GS game. That would be a smart/wise business decision for Nintendo and would benefit them a lot. Also, it’s possible that FP7 (and possibly FP8) are being held back so that they can be revealed with their game simultaneously in a Direct. Isaac with GS HD for example.
Now, is it a guarantee that Isaac is coming to Smash? Absolutely not. You’d go insane if you think so. However, the possibility is really high given all that has happened and should not be ignored. It would also be Nintendo’s best interest to add Isaac as to help promote GS. They know Smash has that power and they’ve done it before with a lot of the characters already. But there is something that we can expect and that is Golden Sun is definitely coming back. It’s now a matter of “when” and not “if”.
Wow! Wasn’t expecting to write all that.