Two Questions - Stack and Triggered Abilities

Hi All, I played a match with a deck I created specifically to take advantage of Changeling.

Question the First:
I had two changelings out and then played [[Banner of Kinship]], selecting "cat" (there are two cats in the deck).

I then played a third changeling ([[Prideful Feastling]]). It remained at a 2/3 until the beginning of my next turn when it became a 4/5 (due to Banner of Kinship).

Is that operating as intended? Do creature type based effects only check at the beginning of the turn? Or does Banner of Kinship only check at the beginning of the turn.

One reason I ask is because creature-based +1/+1 effects are immediate. Should Banner of Kinship also be immediate?

Question the Second:

Later in that match, I had [[Roaming Throne]] in play and selected "Angel" for it.* I had two [[Flock Imposters]] and then played [[Lyra Dawnbringer]].

The Flock Imposters were 6/6 with lifelink, first strike, and flying. They had +2/+2 from Banner of Kinship, +1/+1 from Lyra, and +1/+1 from Elvish [[Archdruid]]... in case anyone is curious.

Is lifelink a triggered ability that is affected by Roaming Throne? When I attacked with the two Flocks, I gained 12 life. Should I have gained 24 life (2x 6 life twice)?

Thanks for the info.

*There were shenanigans with Flock Imposter for reasons.