Lyra makes sure that happens, giving them a power boost and the coveted lifelink ability
Theres also a song action card called The Cold Never Bothered Me Anyway
Teysa works better with some cards than others and being a touch on the luxury / win-more side of things you do have to be a little careful with her
For example, if you start the turn at 10 life, then gain 5 life, and then lose 7 life, you'll distribute five +1/+1 counters, even though your life total is now lower than it was at the beginning of the turn
If and when that changes, you can use those slots for matchups where the sideboarding plans are weaker, such as the above Mono-Red matchup
Permanents that gain counters later in the turn won't become affected by this effect, and permanents that lose all of their counters later in the turn won't stop being affected