We did Alaska on HAL's Amsterdam in 2002. It was our kids first cruise. Not stuffy at all. We had two formal nights on HAL just like the 2 we had on
DCL. I found the attire in the dining rooms and on the decks during the day about the same on both lines.
HAL has kids clubs too, divided by ages. But they don't have as much space dedicated to kids. No kids only pool. Can't speak much beyond that on the kids clubs because our kids elected not to use them on either HAL or DCL. (they were 15 and 11 on the HAL cruise, and 16 and 12 on the DCL cruise). We spend sooo much time apart with school, baseball, soccer, and work, the cruises have been our time to spend together as a family. An except for 1 hour on DCL for wine tasting, were were with our kids 24/7 for both cruises, something we can't do at home.
If they are adding the tip to your bill, that's new. HAL's trademark was you should receive excellent service without service staff expecting a tip. The second part of that was HAL was reportedly the best paying line, paying wages their staff could live on. However, DCL is one of the few lines left that don't automatically add the tip to your ship account. I know NCL does as part of their Freestyle cruising, but you can tell them not to do it and they won't.
I would highly recommend HAL to and DCL veteran looking for an Alaska cruise.