I got Blanche out. She just showed up one morning (I must have found her in a void). I think... 5-6 villagers asked before she did. I still have 4 villagers that never requested to move despite being original to my town. So I think it's more luck of the draw than anything else.
I have always heard mixed answers about this question. for me soleil asked to move the day after she unpacked her moving in boxes but muffy had placed her house plot that day ( not here house- just the land plot ) so im not sure if that would count as the tenth villager moving out or not.
Willow was my tenth and my sister wanted her
I had no problems getting her to move at all, a few others asked before her but she left after not too long
So it's just luck in the end. I'm working on getting Coco to ping me for a friend, hopefully it will be soon enough ^^
Thanks a lot for your answers everyone! ~