Again, my apologies if you already understand these points and it's just not coming across in your English translations, but just to clarify a few nuances here.
>A: 。。。ふう。何ていうか、すごかったね
>...Hmm. You know, magnificient.
何ていうか is an expression used when you're searching for the right words.
Also, すごかったね is past tense, which isn't really coming through in your translation.
>B: ああ、あれが後光が差すっていうヤツだな
>Yeah, that is the thing (/person?) called the halo shines.
ヤツ is "thing" as Toritoribe-san points out, but nuance of this って(いう)ヤツ is close to the English "that's what you call..."
For another example, 「一石二鳥ってヤツだな」="That's what you call killing two birds with one stone."
>A: ああやって、困ってる人達の力に直接なれるのって、いいな。。。
>That way, it can become directly helpful for people who are trouble, so good...
Not sure why you have "it" as the subject here. This seems clearly to be referring to the same person they've been talking about.
"Being able to directly help troubled people like that...that's great, huh."
Note that this いいなぁ~ also carries a nuance of "Wow, if only I could do something like that too...(but I can't)."