How?
If we want to add Snowflake to Hazou's polycule, Snowflake needs to like and be comfortable with Akane and Ino more than anything. We already know Snowflake likes Hazou and Hazou likes Snowflake -- any real chance for a relationship with Snowflake is built on connecting Snowflake to Akane and Ino.
So for anyone that wants Hazou x Snowflake, I think we should have dates or outings introducing Snowflake to Akane and Ino. More Ino than Akane, but both of them together would be best.
This would also make it much easier to eventually add Snowflake to the polycule -- we want a situation where Snowflake is close with Akane and Ino and Akane&Ino are the ones that propose adding Snowflake to the polycule. The reverse situation, where Hazou becomes closer with Snowflake before approaching Akane&Ino about it, is not going to go over very well.
(I repeated Akane and Ino so many times I was tempted to shorthand it to A&I. But that sounds like T&I, and we don't want to introduce Snowflake to T&I.)
IWAIOTISADTIOTFGMKAFAIAOAPLTR!