Kudos to you for embracing the remote culture (partially). However, you should take it a step further and not "fly them out to visit HQ" but instead: Take the

Kudos to you for embracing the remote culture (partially). However, you should take it a step further and not "fly them out to visit HQ" but instead: Take the entire team out for some team-building and working from a different locale (you can stick to the US - as most remote-first companies do). Your company is not exactly the same as the next advertising-eyeballs SV startup, so perhaps getting out of the Silicon Valley hype-train and "pat each other on the back" environment, exploring a different area/wilderness will open your team up to greater innovation and lateral thinking. See Automattic for a reference-point of how to do it.