The clues that look normal
have answers SNIFF OUT(?) / ODD / SIZE / WORDS / ESSENCE. Taking the center letters of each of the odd-length words gives RAYLEIGH WAVES. (And of course, since this has "sniffing out" and references to scent, it must be the smell meta.
The colored clues
are ordinary clues. The answers are COLOR MONITOR, RUSSIA, REESE'S PIECES, BUMBLEBEE, and SECONDARIES. Each of those is associated with three colors, and each has the same number of letters as its clue has words. Taking the corresponding letters to the colors of the words gives CROSS ASSEMBLER.
Since this one relates to colors, it's the sight meta.
The encrypted clues
can all be decrypted with substitution ciphers. The clues are:
- SIGN OF APPROVAL ORIGINATING FROM ROMAN TIMES
- COMMON PUZZLE METHOD USED FOR EXTRACTION WITH NUMBERS AND WORDS.
- NOTE NEAR THE CENTER OF A PIANO THAT HAS A NAME
- A SCORE IN HORSESHOES, OR PERHAPS SOMEONE WHO MAKES NOISE WITH BELLS
- SUPER MARIO WORLD TWO CHARACTER THAT LOOKS A LOT LIKE BIRDO
The answers to those are THUMBS UP, INDEXING, MIDDLE C, RINGER, and PINK YOSHI. Each of those starts with the name of a finger, so this is the touch meta. Taking the other letters (SUP/ING/C/ER/OSHI) and re-decrypting them gives PERFECT CIRCLE.
The clues with missing parts of words
have all had an item of food removed. The original clues are:
- Amicable, often cheers people up, or kind
- Gossip a statement that is not neccesarily true
- A 3d object has height, width and _____
- Animals like weasels although with shorter tails
- Membrane of the corti that form in the inner ear
The solutions are NICE, RUMOR, BREADTH, STOATS, and BASILAR, each of which has a food item in it. (Food means this is the taste meta.) Removing that food item from each gives N OR TH ST AR.
The clues that look like random words
are all homophones of the actual clues, which are:
- Picnic insects
- Dual to ma'am
- Game using a map
- Use clothes
- Howell and Radcliffe
The answers to those are ANTS / SIR / RISK / WEAR / DANS, which sounds like ANSWER IS SQUARE DANCE. And since this was all about homophones, it's the hearing meta.
Putting it all together
Each of the answers has two words, and one of the words in each is a Zener card - the tools used to test for clairvoyance, the sixth sense.
PERFECT CIRCLE
CROSS ASSEMBLER
RAYLEIGH WAVES
SQUARE DANCE
NORTH STAR
Those have a canonical ordering (which I've helpfully arranged them into up there). Reading off the nth letter of the nth non-Zener-card word gives PSYCH, the final answer.
(Thanks to Wesley Situ, n_palum, Sp3000, and Gareth McCaughan for their help in chat!)