My personal preference is to remove them from the water they were born in and place them in new, aged salt water, matching things like temp, pH, salinity, in order to lessen the exposure to any pathogens in the original tank.
When doing the cleaning, wipe down ALL surfaces including all panes of the tank as the bacterial slime starts to build up very fast.
As for a pregnancy, watch for an egg transfer, but in case you miss it, look for any orange eggs that sometimes don't get completed in the transfer and that will give you an idea of when to expect the fry in 15 to 17 days later.
When that time comes, check daily before or as soon as the lights come on because IME, most birthings happen early in the morning.
Sometimes a few get released the day/evening before and can be a warning sign.
While the phyto isn't going to feed the seahorses, it is an aid to using up ammonia produced by the fry when you have more of them.
You can stop using the " First Bites" as the fry will not eat them.
Also, the rotifers need to be live, not frozen, because it takes some time when they are older to be able to be weaned onto ANY non live foods.
As copepods come in many sizes, you need an appropriately size copepod, not larger than newly hatched brine shrimp, and again, they need to be live.