Honestly, this episode is a lot more impressive than it should've been. The synopsis and theme alone sound like an accident waiting to happen, but DHX actually pulls it off quite soundly.

Twilight and Spike are at their A-game. Spike's the straight man who has to remind Twilight of her schedule, and Twilight not only tries to listen to Spike and her checklist, but also take care of Flurry Heart. Clearly, she loves her niece. A lot of the actions seen, including Twilight playfully blowing on FH's tummy, are common.

One problem with Baby Cakes is how clichéd and dull the plot is and how generic the Cake twins were. Flurry Heart has plenty of personality. Even at her age, she's incredibly intelligent, yet she still can't deduce very complicated thinking, like finding an extra balloon rather than split it (thanks, @Jeric ;)). Sure, she had a tantrum, but it was quick and with reason. When Twilight isn't laying with her, she feels left out. And when her whammy's missing, she freaks out and searches for it in a major panic.

Shining, Cadance, and Spearhead are awesome. SA and Cadance show very clearly how much of a royal pain it is to take care of a baby through their tired eyes, split hair, and slip ups. Spearhead has that classic surfer/casual dude accent and archetype, but to echo @Batbrony, he's incredibly likable and not stereotypical. He really enjoys art and how art, especially modern and abstract art, can bring out emotional responses to people. He understands how individual art is and relishes it.

I'll echo J in a chat between he an I on Discord. Based on how the beginning was written and Spike reacted by how his friends's names sounded similar, it may be implied that the writers were probably trying to convince the viewer that Spearhead was going to be generic and flat. This can create an initial impression of who Spearhead is. But then, you get hit with, well…"a whammy." If that's true, clever.

Spike is the victim of some slapstick, but unlike many episodes before it (including Newbie Dash), it was quick, he clearly showed no pain, both he and Twilight were equally victimized, and Spike does get his moment at the end.

The two morals are great, too. "Spend quality time with those you love," and "don't ask to babysit on short notice."

The two issues here are some pacing (particularly in the climax after Twilight yells at her) and the fact that Twilight brought her to other sick foals at the hospital. They're small, but noticeable.

Other than that, great ep! Keep it going! ^^