Although Kaito enters attacking when his ninjutsu ability resolves, he was never declared as an attacking creature (for purposes of abilities that trigger whenever a creature attacks, for example)
Since the plan is to sacrifice a lot of saprolings, keep an eye out for spells that give you opportunities to sacrifice creatures and spells like Blood Artist that give you extra benefits when creatures die
Not all play groups are meant to house Group Slug decks, but just like poking a bear with a stick, you wont know what happens until you try
Thank you for reading, and be strong during these hard times
Effects that modify a creature's power and/or toughness without setting it will apply to the affected creatures no matter when they started to take effect
A finisher like Craterhoof Behemoth will get the job done after drawing lots of cards and getting plenty of elves into play