No matter how fast Barry can move, lighting a candle takes as long as it always does. There's no way he can convert his and Iris's living room into the romantic setting with 100 or so candles lit faster than the eye can see.
Caitlin says Frost still has warrants for her arrest, despite the fact she's been in public as a civilian and hero since the fourth season. Though it's possible she doesn't feel comfortable letting Frost out in public to avoid fans of her.
Also in "Dead Man Running", Frost accompanies Barry to a crime scene and no officers made any attempt to arrest her nor did they notice her.
During Flash's TV interview, the graphics (lower thirds) update with a quote almost immediately after he says it. Since someone would have to type in the quote, this makes it seem that either the graphics were already made or the TV station has a typist with Flash-level speed.
Much like back in "License to Elongate", Barry again does not disguise his voice by vibrating his vocal chords when giving a public statement on the news.
Its possible he just naturally alters his voice and speech pattern rather than vibrate his vocal chords.
Then again since Vibe never bothered to disguise his voice, and Frost has been using a nanotech solution since "The Death of Vibe" to make her voice normal, Barry likely doesn't care anymore.