The second one came from the idea that Glorfindel found his titles uncomfortable and the reverence that they provided a little ridiculous. Although that mainly relates to 'balrog slayer' I didn't want to ask for that one alone because of the echoes that 'balrog' would give his cast mates (Durin's bane/the balrog of Moria for the dwarves and Legolas and either general balrog knowledge for the elves or more about the tale of Glorfindel and the balrog which became a proverb for great skill and courage amongst the elves). Asking for them all in one go gives him something else to focus on (it'd be Rivendell because they already know a fair amount about it).

From a modern day pov and it won't effect Gabriel yet because he doesn't know his name, yellow haired is pretty daft too because that's basically the translation of his name.