new "Only Connect" puzzle

Question

Please be kind - this is my first puzzle!

+------------+-----------+------------+------------+
|   alcohol  |    and    |    arrow   |     cat    |
+------------+-----------+------------+------------+  
|    cave    |   demon   |   federal  |  fireworks |  
+------------+-----------+------------+------------+  
|    guts    |   order   |    paper   |   prince   |
+------------+-----------+------------+------------+
|  seedcake  |   stone   | toothbrush |    upon    |
+------------+-----------+------------+------------+

The rules are as standard: divide these 16 words into 4 thematic groups of four. Have fun - I did!

Answer 1

Got one!

GUTS, SEEDCAKE, FEDERAL, UPON.

They all contain 3 consecutive letters of the alphabet backwards, namely STU, CDE, DEF, NOP.

This leaves:

 +------------+-----------+------------+------------+
 |   alcohol  |    and    |    arrow   |     cat    |
 +------------+-----------+------------+------------+ 
 |    cave    |   demon   |            |  fireworks | 
 +------------+-----------+------------+------------+ 
 |            |   order   |    paper   |   prince   |
 +------------+-----------+------------+------------+
 |            |   stone   | toothbrush |            |
 +------------+-----------+------------+------------+
 

Answer 2

Is this one?

FIREWORKS, SEEDCAKE, TOOTHBRUSH, UPON. Are all formed of two words stuck together.

Answer 3

Here is another possible category, compatible with the one JonMark Perry found.

AND, ORDER, PRINCE, STONE.

These are all words that occur in the titles of the Harry Potter books.

Taking this together with JonMark's answer, this leaves:

 +------------+-----------+------------+------------+
 |   alcohol  |           |    arrow   |     cat    |
 +------------+-----------+------------+------------+ 
 |    cave    |   demon   |            |  fireworks | 
 +------------+-----------+------------+------------+ 
 |            |           |    paper   |            |
 +------------+-----------+------------+------------+
 |            |           | toothbrush |            |
 +------------+-----------+------------+------------+