My son, thankfully, was a self motivated little person. Once he got to that age, he could "entertain" himself in the crib...not crying or anything, just playing. Pre-nap or after he woke... this is what he did. He babbled, played with his stuffed animals in his crib, "sang", and just bopped around in his crib, rolled around, stood up, sat down, and basically hung out. He likes his crib. So I'm glad.
When he was ready to come out of the crib, THEN he would cry for me. Until then, he was perfectly content, and happy. It gave him time also, to "practice" his skills and learn to play on his own... my sister said "he probably does soliloquies in the crib when no one is looking..." because he really would talk and make noises in there. He still does that, and he is almost 24 months old now.
ALso, at certain developmental changes, their habits change, it may abrupt their sleep patterns and what not. Your boy is probably just changing... cognitively, physically, skills wise, and everything. And yes, they "practice" these new skills even in the crib when we would like them to sleep. Babies learn this way...
If anything, it's a "phase." Babies/toddlers go through LOTS of phases.
Every 3 months or so, is a "growth spurt" time too...and at these times they get hungrier and need to feed more. And NO... a baby does not have to sleep through the night yet... most don't. You can train them etc., try all the techniques to get them to sleep... but each baby is different. But your boy seems to sleep well to me. Waking up ONLY once during the night is VERY good. My son is almost 24 months, and he also still wakes up once a night. My daughter, didn't sleep through the night until she was about 2 years old!
If your son is up most of the night with these activities.. just make extra sure he is getting his naps during the day. At this age, 2 naps a day, morning and afternoon.
If it really bothers you, ask your Pediatrician.
take care,
Susan