Not sure if anyone checked out albaseerah's Newsletter concerning this subject but its definitely worth a read...
http://www.albaseerah.org/publication/nl/vol1iss5&6.pdf
As for emaan being the heart then let the Muslims know that emaan is speech and action.
1- Speech of the tongue and speech of the heart
2- Actions of the heart and actions of the limbs
If such a woman is not religiously committed to the point that she doesn't even pray then this is a SERIOUS CRIME. The Prophet sallallahu alayhi'wa'salam said, “Between a man and shirk and kufr there stands his giving up prayer.” Narrated by Muslim (116). And he said: “The covenant that distinguishes between us and them is prayer; whoever does not pray is a kaafir.” Narrated and classed as saheeh by al-Tirmidhi (2621); al-Nasaa’i (463); Ibn Majaah (1079); classed as saheeh by al-Albaani in Saheeh al-Tirmidhi.
So not praying at all is, sub7anAllah, as Imam Ahmad said, apostacy. If what you say is true then may Allah guide her ameen.
As Muslims, we should have gheerah for our sisters. A Muslim woman who adorns herself outside the home its inviting attention, looks, stares, and lust towards her. As a Muslim woman, this should enrage you from within for a few reasons.
1) Violation of hijab which is a sin
2) Violation of the right of the Muslim woman towards modesty
3) The ill effects it brings. Kafir men aren't blind, once they see a woman in a scarf but adorning herself with make up and tight clothing then pretty soon, "hijabis" will become targets as well. And come to think of it, they already have wallaahu'musta3n.
As a Muslim male this enrages you for several reasons including the ones above.
4) What if this were your wife, mother, sister, daughter, etc dressing this way?
5) A Muslim woman BELONGS with a Muslim man aka her HUSBAND. The very thought of uninvited eyes casting prolonged glares at her is condescending to say the least.
6) Sisters dressing in that fashion brings the quality of marriage prospects to a lower level. As men we should have jealousy for our wives; what is a husband who doesn't protect his wife as well as the wife having comfort that her beauty is ONLY for him?
As for the rest that you mentioned then its just adding flurries to an avalanche. We should all ask ourselves the question...if he were my son, would I choose such a girl to be my daughter-in-law? Wa'allaahu 3lam