Given the existing names Kaitlynn, Kieran, and McKenna, here are some sibling name suggestions, categorized for different preferences:

Similar Style (Irish/Celtic-inspired, flowing sounds):

• Girl: Alana, Ciara, Saoirse, Aisling, Rhiannon
• Boy: Declan, Finn, Liam, Eamon, Cormac

Complementary Style (Balancing the existing names' sounds and lengths):

• Girl: Ava, Grace, Olivia, Sophia, Ella
• Boy: Ethan, Caleb, Owen, Noah, Samuel

Modern & Popular:

• Girl: Harper, Aurora, Willow, Scarlett, Evelyn
• Boy: Liam, Noah, Oliver, Elijah, William

Unique & Less Common:

• Girl: Juniper, Indigo, Wren, Lyra, Theodora
• Boy: Arlo, Jasper, Felix, Rhys, Atticus

Considerations for Choosing:

• Initial Sounds: Consider the flow of initials when saying the names together (e.g., Kaitlynn, Kieran, and McKenna have a nice K-sound start).
• Number of Syllables: The existing names have varying syllable counts. You might prefer to maintain this variety or opt for a more consistent pattern.
• Meaning & Origin: Research the meanings and origins of names to ensure they align with your family's values and heritage.
• Nickname Potential: Think about potential nicknames and whether you like them.
• Personal Preference: Ultimately, the best names are those that you and your family love.

This list provides a starting point. Further refinement can be achieved by specifying additional preferences (e.g., specific origins, length preferences, or avoiding certain sounds).