Hognose are day and night compare to BP, they will cruise around during the day, as for hiding they will usually prefer to bury themselves versus hiding under a hide which is why it is important to provide a sufficient layer of substrate between 1 to 2 inches depending on the hognose’s size.
As far as sexing yes it’s a bit tricky when they are smaller and sometime being able to compare to siblings helps simply because some female appear with thinner and longer tails than usual at 20/25 grams however there is no longer any doubts.
I would say female for yours but I would like to see a picture again when she is 20/25 grams, I am a bit on the fence on that one (could be the picture angle) for comparison here is a 9 grams female I held back this year (a bit of a difference but as explain previously sometime they can be tricky)
As far as feeding and if she was well started and you are providing the proper husbandry (temp, enclosure size etc) it should not be any issue. People often have issues because the animal was not well started and or still on scented and IMO they should be on unscented and have ate F/T at least 10 times before being made available.
Enclosure wise I usually recommend nothing bigger than a 14 x 7 foot print until they are at least 50 grams.
Remember that unlike BP they have a high metabolism and because their prey is meaningless nutrition wise feeding every 3 to 4 days will be essential at first and advisable until they are at least 25 grams at which time you can feed every 5 days. If fed right our snake should be able to reach 75 to 100 grams within it’s first year.