While it supports BVH, BVH is the bare minimum, the worst file format for transferring animation data
There's plugin/addon for Daz that'll accept OBJ sequences, but I'm drawing a blank on the name. That said, I'm still trying to out how to move the figures around after converting to Rigify without having the gens stay in place, so I couldn't say how well that works either.
As for OP:
First and foremost, you'll want to grab Limbstick and eR Breast Animator just to make your life a bit easier.
This will tend to fix a lot of the issues that GNVE was referring to with floating characters as you can plant your character's feet on to a plane and have them stick to it. It basically becomes psuedo IK. This allows you to basically forget about moving characters as you can basically plant their hands to a table, or the male figure's hands to the female character's legs, or something of the sort. Like so (here's a
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since F95 refuses to add a media insert for any decent gif websites):
View attachment ezgif.com-video-to-mp4.mp4
In the second gif/image, her hands are Limbstick'd to a plane beneath her hands, which then allow the chest/shoulders/arms to bend a bit more naturally than animating them manually. I believe I did the same to her feet just in case.
As you're just starting, it's probably better to just stick with the basic 'golden ratio' for looping animations. Short, quick clips. 2-3 seconds long. The 60-90-120 stretch, specifically. You'll only technically use 60-119, as 60 and 120 are the should be the same image if you're planning to loop correctly.
That being said, rather than drone on step by step, I'll DM you something that should help get you started faster than I can.