Using OPEN IV replace the downloaded files in the following paths, one is a cutscene model, and the other is an ingame model:

.cs (cutscene model)

find it here: x64g/levels/gta5/generic/cutspeds.rpf/cs_ashley

.ig (ingame model)

find it here: update/x64/dlcpacks/mppatchesng/dlc.rpf/x64/models/cdimages/mppatches/ig_ashley

Update 1.0

- improved face & upper body textures
- cleaned up her outfit

Update 1.5

- added 2 new outfits

Enjoy :)