I've been in the field for a long time. I can safely say that most of the things listed here do not raise my red flags in terms of abuse, but do raise a couple of questions..
A 4 year old who is fascinated by boyfriends is most commonly seen when a big sister (or aunt, or mom, or a favorite movie) is swept away and in love with a boy. She is simply emulating the big girls. I've seen princess movies do it to some little girls.
Sometimes the interest in body parts is just development, but sometimes it is also that a child has caught a glimpse of parts, or a glimpse of people doing things with their parts. I think back to the child I worked with once who was referred to me because she told her day care teacher that she could "lick his weenie". When all was said and done, it turned out that mom and dad liked hanging out in the kitchen when the kids were "asleep" and she witnessed mom giving dad a treat one night. Normal, typical reaction to a relatively typical situation. It could have been a nightmare if mom and dad weren't so honest.
Showing off privates can be quite thrilling, especially when people are all "oh my goodness! shocking! nononono!"...it's like when the littles drop the F-bomb for the sheer reaction. It's funny! (to a 4 year old). Same thing about drawing poops or dog weenies or people weenies or big lady-chests. All it would take is one person to be all shocked and aghast for that to be a favorite theme. At this age, also, there is a keen interest in gender differences. When my own DD was in daycare, she witnessed boys peeing and was very interested in learning how that works. When her puppy had a constant boner and spent all day humping furniture, pillows, and god-knows what else, she learned alllllll about penises and it was all penis-talk for days on end. Poop, pee, butts and underwear are all open-season humor at 4. I had a patient once who played "poopy diaper" for a year. Nope--she was not an abuse victim...but her caregivers were a bit on the Victorian end of things. All those limits were stressing her out!
We have a relaxed policy in our home about colorful language (can't be used in a hostile fashion toward a living thing), but when I decided to enroll DD in kindergarten this year after unschooling for quite a while, we had to run through the words we can't say at school (similar to a George Carlin skit). She made up a song about them, and to this day I regret not having a recording device in the car, as she threw every one of them into the song and honestly, it was quite funny. She has never uttered any of the list at school, as she understood well how there are rules at school and friends' houses about it that we don't have at home. And, I might add...DD very rarely uses said colorful language at home, but when she does, it reflects very nice grammar and is really well-placed and meaningful!
All that said, mom's intuition is usually pretty good. So if there is some cause for concern from an external source, it's good to teach DD NOW about what her parts are, how to keep them safe (I always say "we keep those safe and just for us and our someday-babies!") (But you can't make babies until after your nursies grow big to feed them...so you get to keep those safe for a long time) (DD is baby-crazy, so it works for us), what to do if someone tries to get at them ("Scream really loud! Let's practice! Lemme hear it!") Also, making sure everything is healthy down below helps too. I once had a patient who was masturbating a LOT, but it turned out that after the beach season she had some yeast in the nether regions. Ow! (But not abuse, as was initially thought)
Hope that helps, momma! It can be crazy on the mommyworries when kiddos do this!