The short answer appears to be that once you get past factors which are visible to the naked eye and which everyone agrees on (it's better to be thin than fat, rich than poor etc), romantic attraction appears to be almost entirely idiosyncratic and unpredictable, even among identical twins: https://slatestarcodex.com/2016/10/21/the-heart-has-its-reasons-that-reason-knows-not-of/ http://cogprints.org/773/3/155.pdf It seems possible that this may be an example of a scientific question that is essentially unanswerable as the answers will be mostly the "crud factor", at best explained by effectively undiscoverably complex interactions like epistasis and evolved, like personality, for that reason (see Penke & Jokela), and one might even wonder if it is an example of deliberate developmental instability which evolved as a kind of bet-hedging.
EDIT: more discussion: https://www.lesswrong.com/posts/6yiayg5QWtWme4JN8/anatomy-of-a-dating-document?commentId=ctD7rHdPpwdSW8jMt
This is what I was looking for. Thank you, Gwern!
The heart has its reasons that reason knows not of
You could also ask: Can bicycle riding be explained? What factors lead to bike riding? Proximity, physical attraction, happenstance, personality, wealth, health, values, shared experiences, individual preferences?
You can likely run correlations with those factors but they are not going to explain you much about the nature of bike riding.
Reading Mate by Tucker Max and Geoffrey Miller might provide you with a better perspective on the subject.
Clarification: are you asking about the feeling of craving interaction with another person, or the compassionate feeling of wanting to help when you notice their suffering? The growth of each of those feelings is often referred to as "falling in love", but are quite different experiences.
From your list, I remember reading that the primary factor is proximity, though I don't have a source right now.
Proximity, physical attraction, happenstance, personality, wealth, health, values, shared experiences, individual preferences.
What factors primarily determine falling in love with someone?
I'm looking for reliable scientific sources quantitifying the relative contribution of these factors for short - and long-term couplings.