That would be possible, legally. There would still be plenty of discrimination toward a citizen-adopted refugee, though. He/she would, for the most part, be counted as a citizen in legal matters, but many would consider him/her a refugee. It could be an interesting thing to explore.

Ohhey, I should answer the first question, too. ONE SEC. XD
How does the government of Escova view marriage?Marriage is a legal and religious union. In a marriage, a woman essentially transfers from the control of her family head (usually her father) to her husband. She's bound to him in terms of financial holdings and possessions and whatnot.
Is it considered a religious or civil practice?Marriage itself would be a religious practice with civil implications (that transfer of property, etc. etc.). People could have a sort of civil union, having a personal union and handling their assets as married persons would, but it wouldn't be recognized as marriage by most, and it would likely be frowned upon (if you consider that most people would follow the Pryist religion).
Are there any specific practices or ceremonies tied to these unions?I haven't thought about it before now, but I imagine there would be quite a few traditions of ceremonies for marriages. Bodies of water would be common sites of marriage in addition to actual temples. Practices might vary based on locations, but for now I'd urge people to keep the importance of water in mind, as the seas were supposedly created by both the spirits according to the Pryist creation story and water has
massive spiritual relevance at all stages of life.
Should one assume this is a predominantly heteronormative society, and same sex partnerships get a big frowny face?For devout Pryists, it is absolutely a heteronormative society. That doesn't mean that there aren't plenty of people who stray from that, both openly and secretly, but according to Pryism, men and women are supposed to come together much like the two spirits and the Seer and the Martyr. They're taking their cues from the creation story, and the history of the Seer, noting the way that their religion suggests men and women come together to create some sort of balanced whole. Refugee cultures would vary
a lot, and more than a few would likely deviate from these ideas.