The more I've watched improv, the more I've come to a simple conclusion. The quicker everyone gets in, the quicker the team becomes a team.
The singular problem with harolds and musical narratives is that they don't have a weighted group agreement happening.
If you're in musical, you have the opening number. Yes. But, if you're opening number just gives a small detail or maybe a single character, that's not affecting the show. I've seen teams and I've been on teams that throw away the opening number and use it as a jumping off point of inspiration and it never affected the audience.
If you're in regular improv, you may be shackled with opening-less Harold. Which means everyone doesn't get onstage until the group game, and even then some people may not get out.
If you're on a team that has ANY hesitance, try starting with a group game. And not just any group game, a GAME THAT INVOLVES THE GROUP. If a person initiates a group game with such premise that people feel the PRESSURE to be funny, it'll feel like they weren't taking part. Group games that are organic, walk on centric, presentational, or started with half initiations are the best.
Group mind is what causes you're own team to surprise themselves. Sure, you may have a curveballer, I've definitely been one of those. But, they aren't suppose to be the only ones surprising. You want everyone to come to a conclusion at the beginning that we are all having fun, we are all surprising ourselves, and we all had a part in this fun start to the show.
There are older teams on Megawatt (magnet theatre) that have kind of figured out a way around this. They do a group monoscene. They do some sort of active scene painting. They push for walk ons in early scenes. They do 4 scenes then group as opposed to three. They deconstruct a group game from the get go. The Wrath recently did 4 long scenes a group game THEN just straight to third beats. Everyone knew they were going to get in and everyone knew that they was a high pressure at the end to get a LOT out.
Occasionally, a team will get walk on crazy with those first beats. First off, this isn't a bad thing. A want to play with your team is great. Most walk ons could be done as 2nd beats. But, environmental walk ons that just YES AND what's going on now are GOLD! Sometimes a team will get that note, "No one walks on in the first beats". This is a combination of someone who is eager and possibly not getting good responses and someone who is a little sensitive about their scene and unable to react to walk ons.
In Conclusion, you have 2 choices with a team. Figure some group start and allow your team to surprise itself and start the show on a ride that everyone made up. Keep that group game late and rely on the power of 2 person group mind in three increments to get something interesting started.
Here's a quick equation. 1 person is one point of view, 2 people is two points of view. We live in 2 people pov in 99 percent of our daily life. For something weird to happen there will be because we caused it. 3-8 points of view, rarely happens and ends up being much simpler simply due to the fact that people are trying to understand each other. Do your team a favor, get everyone out there.