Hello Teyon, sorry I missed your question.

if you load Rex and Roxie "released versions", the lashes are selected as default and you get faceroom incompatibility.

As you said, select the heads, and all is pretty good.

As for the Miki 4 friend?

Yes Miki4 is quite popular and she could do with a boyfriend.
Actually, Miki4 is quite a good mesh. A bit dence for my taste, but, :-) hey we have Rex-Roxie now. 
But for a Miki4 boyfriend to bend well, the rigging would have to be adapted.

Hint: and all magnets removed or corrected.
If my memory is still OK after 54 years and at close to 2AM, she has unfortunate magnet symmetrical errors/ Magnets and magnet zones left-right are not the same.

Poser 1, 2, 3, 4, 5, 7, P8 and PPro2010, P9 and PP2012, P10 and PP2014 Game Dev
"Do not drive faster then your angel can fly"!