With a functioning mesh importer this method is outdated.
Ashley's Hair Mod is located here: link
Jack's Hair Mod download: link
Miranda's Hair Mod download: link
Adding these hairs via the standard Gibbed method has some...interesting results. Here's a video if you're curious.
There is currently one work-around that I am aware of currently, and that's "wearing" the hair as a piece of armor.
This has a few drawbacks. One, it's inconvenient, and two, in cut scenes where Shepard is automatically loaded or forced into a casual appearance your poor Femshep will have lost her wig.
However, if you just don't care about suddenly bald Shep, or only want to have her look fab for certain parts of the game, keep reading.
The first thing you'll need to do is edit your coalesced.bin file. That's another tutorial in itself, so I'll save that for another day. Instead, here's mine: link
Ashley, Miranda and Jack hair are now three additional shoulder pieces.
Now, you can wear Shepard's regular armor without a shoulder, or you can do this:
The last slider for Legs and Arms are invisible pieces. Added to the Chest are fullbody armor appearances and casual appearances. Now Shep doesn't look like anything's missing.
If you want to get creative, maybe adding the missing shoulder to the head slot so you can use the classic N7, you'll have to dive into editing your own coalesced.
So this is seriously inconvenient. A few keybindings make it less so.
Numpad 9 is forced armor. Hit it, save and re-load and Shepard will be in armor regardless of where she is.
A few times of Numpad 9 + F5 (autosave) + F9 (load last save) and it will be second nature.
It's possible to give Shepard hair and wear her 'shoulder-hair' on top so she never goes bald.
Possible combos: Cyberbabe + Miranda, PROCustomSexy + Ashley...
|Allers + Ashley|
Even though you are wearing the hair as an armor,
you still need to change the Hair_Diff and Hair_Mask entries in Gibbed to match, or use a compatible hair diff. If you don't, it will look weird.
Mesh Names for reference: