The Pub Quiz and the Passion, take two

Question

My attempted pub quiz/Only Connect wall question never got very close to a true answer, so here's another try. The ultimate wall was solved in less than an hour over in the Only Connect Facebook group...maybe this will be a little easier.

1. What flower found in the southern United States do you get if you combine the makers of the Snowball and Yeti models of computer microphones with an Agrabahni Disney Princess?
2. What's the demonym for a person from Denmark?
3. What's the given name of former supermodel Crawford?
4. What 1973 animated Disney film stars an anthropomorphic fox in the title role?
5. Okay, full spoilers: What's the surname of the Half-Blood Prince?
6. Which saint is said to be buried under the basilica in Vatican City that bears his name?
7. Also referring to a person from a grube, a pit, what's the surname of the man who wrote the song Silent Night?
8. Speaking of Silent Night, what kind of song beginning with C is it an example of, a song sung primarily during the holidays?
9. Succeeded by an exclamation mark, what sole word is the title of the book by Upton Sinclair that was the basis of the movie There Will Be Blood?
10. In the cartoon Rabbit Hood, what villain does Bugs Bunny repeatedly thwart, finally dressing up as a king and repeatedly "knighting" him?
11. Who's Ike's partner in chewy candies?
12. In The Simpsons episode "Mr. Spritz Goes to Washington," who does the Republican party rename every Millard Fillmore school, the Mississippi River, and Frankenstein after?
13. What 2017 movie features director Taika Waititi as Kronan gladiator Korg?
14. What completes this sequence: Apr, Mar, Feb...?
15. What's the name of Steven's father in Steven Universe?
16. What word meaning "barren" is also the surname of fictional characters named Tony and Ned?

Hint:

One of the the categories is what we in the Only Connect fandom call a "word one," meaning that the meaning of the word has nothing to do with the connection, but the spelling or pronunciation do, sometimes with a slight transformation. For example--HALE, RITE, INTER, and OVEN are otherwise unconnected words that all become new words when a W is added to the beginning.

Answer 1

To begin with, here are the answers to the trivia questions:

1. BLUE JASMINE; 2. DANE; 3. CINDY; 4. ROBIN HOOD; 5. SNAPE; 6. PETER; 7. GRUBER; 8. CAROL; 9. OIL; 10. SHERIFF OF NOTTINGHAM; 11. MIKE; 12. RONALD REAGAN; 13. THOR: RAGNAROK; 14. JAN; 15. GREG; 16. STARK.

Now we enter Red Herring Central:

There are six members of The Brady Bunch listed:

CINDY, PETER, CAROL, MIKE, JAN, GREG.

There are five Alan Rickman movie roles listed:

DANE (in Galaxy Quest), SNAPE (in the Harry Potter films), GRUBER (in Die Hard), SHERIFF OF NOTTINGHAM (in Robin Hood: Prince of Thieves), RONALD REAGAN (in The Butler).

There are five of Marvel's Avengers listed:

PETER (Parker), CAROL (Danvers), DANE (Whitman), THOR, (Tony) STARK.

At least (as far as I can see), there are only four Cate Blanchett movies listed! These being:

BLUE JASMINE, THOR: RAGNAROK, CAROL, ROBIN HOOD.

So it looks like we could possibly make the wall work using these 4 groups...

However, with these 4 groups like this, there is still one item which fits in none of them (OIL), so one group must be incorrect. Now that a hint has been dropped, and we know that one of the groups involves wordplay, it is clear that the wall should actually be resolved as follows (dissolving my proposed 'Avengers' group in the process):

GROUP 1 (Brady Bunch characters):
CINDY, MIKE, PETER, GREG.

GROUP 2 (Alan Rickman roles):
DANE, GRUBER, SHERIFF OF NOTTINGHAM, RONALD REAGAN.

GROUP 3 (Cate Blanchett movies):
BLUE JASMINE, THOR: RAGNAROK, CAROL, ROBIN HOOD.

GROUP 4 (One letter away from a bird name):
JAN (jay), SNAPE (snipe), STARK (stork), OIL (owl)