Halachically, [*Kiddushin chapter 3 Mishnah 5*](http://learn.conservativeyeshiva.org/kiddushin-chapter-three-mishnah-five/) says that the eved must be freed first before any marriage can take place. Once he has been freed, he is like any other Jew and it would not be any different from any other marriage. Any kiddushin done while he is an eved is invalid.

> הַמְקַדֵּשׁ אֶת הָאִשָּׁה וְאָמַר, כְּסָבוּר הָיִיתִי שֶׁהִיא כֹהֶנֶת
> וַהֲרֵי הִיא לְוִיָּה, לְוִיָּה וַהֲרֵי הִיא כֹהֶנֶת, עֲנִיָּה וַהֲרֵי
> הִיא עֲשִׁירָה, עֲשִׁירָה וַהֲרֵי הִיא עֲנִיָּה, הֲרֵי זוֹ
> מְקֻדֶּשֶׁת, מִפְּנֵי שֶׁלֹּא הִטְעַתּוּ. הָאוֹמֵר לְאִשָּׁה, הֲרֵי
> אַתְּ מְקֻדֶּשֶׁת לִי לְאַחַר שֶׁאֶתְגַּיֵּר אוֹ לְאַחַר
> שֶׁתִּתְגַּיְּרִי, לְאַחַר שֶׁאֶשְׁתַּחְרֵר אוֹ לְאַחַר
> שֶׁתִּשְׁתַּחְרְרִי, לְאַחַר שֶׁיָּמוּת בַּעֲלֵךְ אוֹ לְאַחַר
> שֶׁתָּמוּת אֲחוֹתֵךְ, לְאַחַר שֶׁיַּחֲלֹץ לָךְ יְבָמֵךְ, אֵינָהּ
> מְקֻדֶּשֶׁת. וְכֵן הָאוֹמֵר לַחֲבֵרוֹ, אִם יָלְדָה אִשְׁתְּךָ נְקֵבָה
> הֲרֵי הִיא מְקֻדֶּשֶׁת לִי, אֵינָהּ מְקֻדֶּשֶׁת. אִם הָיְתָה אֵשֶׁת
> חֲבֵרוֹ מְעֻבֶּרֶת וְהֻכַּר עֻבָּרָהּ, דְּבָרָיו קַיָּמִין, וְאִם
> יָלְדָה נְקֵבָה, מְקֻדֶּשֶׁת:
> 
> [With regard to] one who betroths a woman, and [later] says, "I had
> thought that she was a Kohenet [daughter of a Kohen] and behold she is
> a Levite;" "A Levite, and behold she is a Kohenet;" "Poor, and behold
> she is rich;" "Rich, and behold she is poor;" [in all these cases] she
> is betrothed, because she did not deceive him. **[With regard to] one
> who says to a woman, "You are hereby betrothed to me after I convert;"
> "After you convert;" "After I am freed;" "After you are freed;" "After
> your husband dies;" "After your sister dies;" "After your yavam
> performs chalitzah [the ceremony performed to release a widow of a
> childless man from the obligation of levirate marriage];" [in all
> these cases] she is not betrothed**. Similarly, [with regard to] one who
> says to his fellow, "If your wife gives birth to a female, [the child]
> is hereby betrothed to me," she is not betrothed. If his fellow's wife
> was visibly pregnant, his words are valid; and if she gives birth to a
> female, she is betrothed.