THP -- Two For One

The clues are straightforward, although some are a bit tricky. The "even-odd" that precedes the clues tells you whether the solution word has an even or odd number of letters, thus narrowing down the list when there is more than one possibility. The solution words are:

1  useless
2  drink
3  moonshine
4  prescription
5  scream
6  conserve
7  parking
8  legend
9  wintrier
10 yellow
11 Em
12 foot
13 pastel
14 golfer
15 instill
16 contestant

Now what? Well, after looking at the words, you may notice that a few of them can be split into 2 smaller words: such as LEG-END, WIN-TRIER, etc. Each of these phrases pairs with another of the words on the list:

LEG-END = foot
WIN-TRIER = contestant
DR-INK = prescription
IN-STILL = moonshine
USE-LESS = conserve
PAR-KING = golfer
YELL-OW = scream
PAST-EL = em

So, what's left? Well, the clues are numbered, which must be for a reason. Adding the numbers for the pairs seems logical, and when you do, you get 7 different sums. Arrange those numbers in order, and extract letters from the solution words according to the spelled-out ordinal numbers preceding the clues (keeping the two letters in each pair in lower-higher order), and you get:

6  DE
7  SC
15 RY
18 ON
20 EF
21 IR
24 ET
25 WO

Which spells: Descry one fire two.

So, we're at it again. Using the same wordplay we used the first time, what is a single word that means "descry," that can be split into two words meaning "fire"?

The answer is NOTICE.

Did you notice the hints along the way? The title "Two for one," suggests a pairing of the words, or a splitting of one thing into two, which is what was done in the course of solving the puzzle. Also, the "party game" described in the backstory was Charades -- and the type of wordplay in which two words are combined into one, such as NOT ICE = NOTICE, is called a "charade" (especially in the context of solving cryptic crossword puzzle clues).