Is there anything missable in the HotS campaign?

Are there any achievements, side missions, easter eggs, or anything of that sort that I have to get while playing through the campaign, that I can't get by replaying missions after I've completed them?

I would assume achievements like Rally the Troops would be missable, since you have to speak to people before doing something.

But more than achievements, are there any hidden levels or jokes, things that you have to do something specific at a certain time or you'll miss them?

Spoilers as appropriate!

Solution 1:

General advice

• Talk with everybody on your Leviathan beetween missions! Check it twice.
• Click few times at Kerrigan and other heroes to hear funny dialogue.
• Earn and play all evolution missions. Check it twice! You can miss it.
• Make all additonal tasks in missions to hear dialogues.
• Don't end missions too fast to make all dialogues happen ;)

Easter eggs list

• Find Dehaka's right arm that is "Still bleeding profusely" in "Supreme" and him running in brushes in "Walking The Ancient"
• Discover that 2 primal zerg leaders in Zerus are Tasteless a.k.a Tastelopes vs Artosis a.k.a Artosilopes - pro SC2 players.
• Find out that Blizzard also likes Minecraft with exploding green loctus named Creepers in final Zerus mission.
• When playing as a Hyperion your fighters will say Star Wars and Futurama quotes.
• Be a vandal! Destroy a shiny new marine car/Helion in the second Ultralisk evolution mission and hear him cry about it. Screenshot?
• Say hi to old Starcraft Brood War satellite.
• Find out that Zerglings are really allergic to lemon juice and UNN report from Wings of Liberty was right!
• Hear that there are "so many banelings" like in the 1st GSL Open Finals.
• In "Enemy Within" mission find Diablo!
• In the Roach evolution mission find Maye, Oynx & Diamond - this is done for Rebecca Mayes who did THIS :D