Jaquelyn Hyde had previously appeared in #2.21;"Too Many Cooks," as another character.
It was typical practice for the audience to applaud any of the main characters or Guest Stars as they made their opening appearance in the scenes of an episode. This was not usually done if the actor was in a small supporting role. However, When this story opens, Jack Albertson does not receive his usual applause. This would happen periodically for some of the other stars as well. It is seen to happen in #2.21; "The Face Lift," with Jack Albertson and Freddie Prinze in the Opening Scene.
Chico had previously dated Liz Garcia in Season 2. He will also date Lisa Malone in #3.4;"Chico's Problem." Both of these ladies are RNs as well.
It can be seen by astute observers of Chico and Ed arguing in the garage, that Ed's motivation is very fatherly towards Chico. It can be seen at the end, when Chico walks out, that Ed did not intend or expect that the conversation would end the way it did. The intimacy of their bond had grown and could be seen. The two actors even received a rousing round of applause from the audience, for their portrayal.
Ed shares with Louie that he has been like a father to Chico in the two years they have been together. He also refers to himself as Chico's own "flesh and blood." This is one of the most tender and heartwarming moments of the episode, not to mention the series.