I think the ears and the length of coats can come from both bunnies.
The colour is more complicated but I'll use humans first.
eg. (very simplified) Blue eyes are usually recessive. Humans inherit 2 genes for eye colour. Call Blue A and Brown B
AA + AA = AA (All babies have blue eyes)
AA + AB = AA or AB (Half blues eye, half brown)
AB + AB = AA, AB or BB (Quarter blue, 3 quarters brown)
AB + BB = AB or BB (All brown)
buns are more complicated and have 4 genes AABBCCDD (and variations of) capitals are dominent,
A - A (Agouti), at (otter and tan) and a
B - Black (B) or brown (b)
C - Full colour (C), chd (chincilla), ch (himalayan), chi (sable)
D - D (strong colour), d (weak e.g lilacs and blues)
E - Extrension of colour along shaft.
REW must have "cc" (recessive but when together erase all other colouring so becomes completely dominent to A,B and D, E). They can have any A, B or D combination
Black must have the following genes ABCDE
Otter must have "at"
Harlequin must have Chd (ressessive but dominent to c)
The answer is that it is very possible for those colour combinations to occue. You REW could be A or At and as long as your grey has CHd somewhere you can get the harlequin. If you bred the rew with a rew however, all you would get is a rew.