I think that Mario Maker as an inspiration for the Bant shard may not be a good pick, mostly because it's a series about "making games" and the cards will be mostly meta cards, that is interesting but maybe a big loss in flavor. Furthermore, the Bant shard is centered around white as a color and picking a 4-type-permanents matter as a core mechanic for these colors may result in a very strange color pie in the cube (or a weaker white, since most mono-colored card won't be super useful in the Bant mario maker archetype).

My suggestion is to use Peach & Mushroom Kingdom as the core source of inspiration for the Bant shard. This may prove helpful for the following points:

• Most white creatures are low cost and effective, that's why the white weenie as an archetype exist since forever, with highs and lows (Oketra's Monument in standard recently was very good). What white creatures based around mario maker can we make? How will the 4-type-permanent matter them support the basic effect of the white color pie?
• Azorius color pair (Blue-White) is shared between Mario kart (Esper) and Mario maker (Bant). With Peach & Mushroom Kingdom as the source of inspiration for Bant, the Azorius color pair can be sport centered (i.e. golf and tennis), with the pursuit mechanics on sport flavored card.
• Selesnya color pair (Green-White) is shared between Mario allies (Naya) and Mario maker (Bant). With Peach & Mushroom Kingdom as the source of inspiration for Bant, the Selesnya color pair will be easily yoshi centered (and the dual land you designed is already a yoshi one). With yoshi's and suitable power-ups in classic mario games, this work wonders in theme and mechanics. I see how you may have an artifact centered Azorius, but Selesnya as Mario Allies and Mario Maker is kinda out of focus thematically and mechanically.
• Simic color pair with Mario Maker (Bant) is... something? Complete lack of theme and flavor. Go full Yoshi's Island here: soap bubble, baby creatures, eggs as 1/ 1 counters to throw around.
• Designing cards around a game with characters and mechanics is way easier than using mario maker. You have creatures, allies, monsters, npc, events, objects... You have Peach and Daisy, a toad tribal subtheme for mono-white, peach's parasol, yoshis, baby mario, tennis and golf shots, peach's castle, mario party dice...
• Green creatures (such as Goombas and Koopas) may be able to be cast in a Bant deck. Since it's Mushroom Kingdom-based, it's perfectly on focus.

On the premise that Yoshi's Island may prove better as a a starting point for bant. You won't require to scratch the Mario Maker cards, just to remove the Architect where it appears on the cards (since it is already an ability word and not a keyword).

The bant keyword should be something based around the moodiness of Peach (have you ever played Super Princess Peach?) and represent her mood in some way. This is very relevant for Baby Creatures (baby mario, baby luigi, baby everyone...) and other characters as well.

Moody: You may have this permanent enter the battlefield with an additional  1/ 1 counter on it. If you don’t, it gains flying.

Adding a flicker sub-themes on the bant colors add to the moody keyword, since you may change in between the counters or flying or gain again the counter if it has been spent in some way. Also, its flavorful since it works as a way to recover kidnapped princesses from scary monsters.

This is my list of Peach & Mushroom's Kingdom themed Bant cards:

1. Bant leader. Princess Peach
2. Princess Daisy
3. White spells. Wrong Castle, Peach's Royal slap, Scapetoad, Temper Tantrum
4. Baby Mario (someone said Bogles?), White Stork
5. Worldwide Competition (Azorius sport-themed card, based around Rhythm of the Wild), Toad Mechanic
6. Yoshi's are green. Green Yoshi, Blue Yoshi, Red Yoshi, Egg Shot
7. Koopas are green as well, some are also minions. Koopa Explorer, Koopa Enchman
8. Toads are white, no minions. They can interact with Goombas since they are both fungus. Toad Sage, Toad Invasion, Toad Villager

The list can go on.

Thank You For Coming to My TED Talk.