lander as kids is my favorite thing ever so here are some things i imagine them doing as kids :
❀ from ages 7-10 they had a secret handshake and still remember it
❀ they would randomly make each other friendship bracelets and they still have them
❀ once on Christmas eve zander wanted to make luke a scarf as a gift with his initial colors, so he specifically learned how to knit from his mom, and on the day he gave the gift turns out luke also made one for him with HIS favorite colors, and they both still keep and protect those scarves. (very specific ik ive thought abt this a lot)
❀ since luke also likes songwriting, i imagine him as a child giving lots of cute little letters to zander (totally as a best friend thing ofc ....)
❀ as kids they had many inside jokes and still have them
❀ before they were dating around ages 14-15 they had playlists with songs that remind them of each other.
❀ used to talk to each other for HOURS on flipphones in the early 2010s.
❀ as kids they talked about how they're life would like when they're older, often talking about how they'll be roommates or live next door to each other.
❀ even if they just saw each other yesterday, they'll run and hug like it's been ages since they last met.
❀ they invented nicknames for each other that only the two of them understand, even if no one else finds them funny.
❀ they took many and i mean MANY polaroids as kids.
bonus :
they know each other's favorite anything, from favorite ice cream flavors to least favorite chores, they can list all the tiny details about each other.