id find a wig that is like that front then alter from there. you will want to use a foam core and then put the wefts onto it (but cut out the wefts from the back of the wig.
Adelheid (KHR!)- 85% done
Fem!Austrian War Succesion France (Hetalia/Nyotalia)- 10% done
Fem!Izaya (Drrr!)- 90% done
Magent!Teto (Vocaloid)- 95% done