I love your chart,
Hedgehog Instigator. Some of the personalities make sense to me but some are completely different to my perception. 7 for instance, is gold for me, and quite a "serious, powerful" shape/digit. Nothing kawaii about it.

I don't have such strong personalities for digits... Anything I perceive there isn't easily defined, which is why I love the chart you made. I really admire that you can so clearly define the distinct personalities.
Like
tree, I perceive colours for digits but they don't really blend for multi digit numbers, just as for me individual letters are associated with colours but they don't blend when within words. When I "look" closely, the digits and letters have a black/dark contour to define their shapes but the associated colour isn't restrained to the confines of the contour. So there is a soft blending where digits and letters meet but this doesn't re-colour the whole number or word.
Something I haven't explored much is colours associated with kana, kanji and other forms of writing. I read Japanese (disclaimer: I was fluent but haven't used it much for the past decade so it's being buried in my memory) and I know there is some colour association there. But it's confusing because it's not only the visual representation of a sound that provokes the colour perception... I'm a visual thinker so that contributes to the confusion.
For example, は is pronounced "ha". When I look at it I don't really perceive much but if I concentrate I can see/feel some blue. However, the sound "ha" is associated with the letters h and a, which are wheaten and yellow respectively, so when I hear "ha" I perceive a wheaty yellow.
Then there are more confusing examples. The number/digit eight is written as 八, pronounced "hachi", but can also be pronounced "ya" depending on the context. For me the digit 8 is very dark green, but as you can imagine the sound "hachi" is different, and the sound "ya" is different again.
I could go into more examples but that's enough about me.
Hedgehog Instigator, I'm curious about whether the colours and personalities you perceive are purely associated with the visual representation of the digits and numbers or whether there is also association with the sounds, and if there
is an association with the sounds is it because it reminds you of letters and their associated sounds and colours? I apologise if the question is confusing.