(very large; recommended to view image in new tab) Here is a PNG that I labelled showing what I believe are all the colorable regions (let me know if I missed any!). The only purpose of this PNG is to identify the colorable regions by labels 1..9a..zA..V (excluding l and I). Generally I let 1 be the background, 2 the ground if separately colorable, and 2/3 the largest region of the dino. Beyond that, there is no rule to the labelling. I tried to keep labels relatively close together, and the sclera usually has an earlier label than the eye itself (sorry for the mediocre positioning). #2, #6 and #14 were the only ones I found that have phantom bounded regions that are forced to be the same color as the background "1" (they are indicated in the PNG). Using 2x3 or 3x2 overlapping rectangles as the basis for when regions touch each other, I made a list of adjacencies. Each pair of regions that touches each other by this rule is specified, with the earlier label (that comes earlier in the ordering 1..9a..zA..V) on the left of ":" and the later label on the right. I have also included a number of possibly debatable "touches" that are not covered by the above rule. All of them concern the eyes. The debatable ones are in brackets () and also has a question mark somewhere in there. #3, #9, #10, #11, #12, #13 and #16 are affected.

#1

1:23456789abcdefghijmnopqrstuvwxyzABDEF
2:347cgopqrstuvwyABDEGHJKLMNOPQRSTUV
3:4
4:5678
7:8abc
8:9
9:a
a:b
c:degh
d:e
e:f
g:h
h:ijk
j:km
k:m
m:n
o:p
q:r
w:x
y:z
B:C
D:EF

#2

1:23456789abmnprtuv
2:34567bcjnprstuw
4:5
6:7
7:89aw
8:9
9:a
b:cdefghijkm
e:f
n:ov
p:qv
s:t
t:u

#3

1:23456789abcdefghijkmnopq(s?)
2:37beijkmnopqrs
3:456
4:5
5:6
7:89abc
8:9
9:a
a:c
b:cd
c:d
e:fgh
f:g
g:h
(r:s?)

#4

1:23456789acdefghijkopqs
2:3567bcdefghijkmnopqrs
3:45
6:7
7:89abc
8:9
9:a
c:d
d:e
f:g
g:h
j:k
k:mno

#5

1:234bcdefghijkmr
2:3579a
3:4569abcdefghmnor
5:67
6:789
7:89
8:9
9:a
i:m
j:m
k:m
m:no
n:op
o:q

#6

1:2345679acegijmnopq
2:36
3:45689abcdefghijmopq
4:56
j:km
k:m
m:n

#7

1:23456789cdhiknopq
2:34569abcdfhjkmqr
3:4
4:5
6:7
7:8
d:ef
f:g
h:ijr
j:k
k:mnopq

#8

1:23456789abcdefghijps
2:36
3:456789abcdefkmnopqsu
5:6u
d:e
f:gkm
g:hm
h:imn
i:jno
j:op
k:m
m:n
n:o
o:p
q:rs
s:t

#9

1:2368efghijkmnoptvy
2:3589abcdg
3:456789abfghijkmntxy
4:5
6:78
7:8
8:bcd
9:a
a:b
c:d
e:f
g:hijkmnt
h:i
i:j
j:k
k:m
m:n
o:p(q?)rt
p:q
r:st
t:uvwx
v:wy
w:xy
x:y

#10

1:23eijkmnopqrvx
2:3456789dfghi
3:456adejkmnopqrsuvwx
4:56
5:6
6:789ab
7:8
8:9
9:bd
a:bcd
b:cd
c:d
d:efg
e:ghi
f:g
g:h
h:i
k:m
m:n
o:p
p:q
q:r
s:tu
t:u
(u:v?)

#11

1:234589bcegiknqst
2:59a
3:458cdefghijkmnopqrst
4:5
5:6789
6:79
7:9
8:9
9:a
b:c
o:(p?)q
(q:r?)
s:t

#12

1:23456789abcdefgmnopq
2:789acdefghikmnopqrst
3:6
4:6
5:67
6:7
7:8t
8:t
a:bc
b:c
c:d
f:ghi
(g:h?)
h:jk
i:jk
(j:k?)
m:n
n:o
o:p
p:q

#13

1:2345fghinopqrstu
2:356789bcdeg
3:5abcdefghiknoprst
4:5
5:6a
6:789ab
7:8
8:9
b:c
c:d
f:g
h:i
i:(j?)k
(k:m?)
n:o
p:q
s:t
t:u

#14

1:23456789abcdefghijprtuvwxyz
2:5bghijkmnoprv
3:4
4:5
5:6b
6:9ab
7:8
8:9a
9:a
b:cdefvwxy
c:d
d:e
h:j
i:k
j:k
k:mn
m:n
n:o
p:qrz
r:sz

#15

1:23defghijkmnopsuv
2:3457bde
3:4789abcdghijkmnopqsuv
4:567
5:7
6:7
7:89
8:9
a:b
c:d
d:e
g:h
m:n
n:o
q:rs
s:t

#16

1:2345689cdejmn
2:3abcdefghijkmn
3:45789a
4:57
5:678
6:8
8:9
9:ab
a:b
(f:g?)
(h:i?)
j:k

From discussion so far, it seems that the eyes should be deemed touching whichever regions make up the sclera? Or anything nearby? In that case, the rule would need a bit of updating. (The goal is to have a rule that aligns with common sense.)