Answers inside.
- Reason for a blackout at a backyard gathering? >> Leaky Teaky
- Star Trek timepiece? >> Spock Clock
- Dead TV mailman? >> Stiff Cliff
- Regrets one’s failed attempts at making gravy? >> Rues Roux
Randy submitted an alternative answer for Star Trek timepiece, which I absolutely love and consider better than mine >> Keiko Seiko.
I apologize a little for the last one in my ignorance that the plural for a “roux”, is still just “roux”. Just figured that one out now. Should have been clued “Regrets of one’s failed attampts….” for Roux Rue. Oh well.
(3) Uber
(2) Randy, Beau, Viola, Novak
Adobery's Puzzle Zone 
While the plural for “roux” is indeed still spelled “roux,” it’s actually pronounced with a final “-s” sound in the plural, but without it in the singular. So to be super technical (and why not!), the closest rhymes using the word would be either “rue roux” OR “rues roux”. Since the original clue has “regrets” (first person singular) and “attempts” (plural) the answer “rues roux” works just fine without the addition of “of”.
I AM A MILITANT GRAMMARIAN.
(also “teaky” isn’t a word. You’re thinking of “tiki.”)
Well, at least my original clue/answer was right then. I decided to look up roux before I posted the answers, saw the plural was spelled the same and had no idea if it was pronounced in the plural to work with my clue. :::cue NBC PSA music:::
I know how to spell tiki…caught up in the visual matching along with the rhyming or something…oops.