It's better to talk about "head-initial" and"head-final" languages, since being OV and VO is just another item on that list of characteristics that tend to go together (typologists don't appear to worry about the subject when it comes to this: it's the relative position of the object and the verb that are thought to be important). Allow me to redo your list for you:
0. Head-final languages usually have OV word order.
Examples: Turkish, Japanese, Latin, Ancient Greek.
Counterexamples: ?
1. Inflectional affixes or aux. elements are placed after the verb in head-final languages.
Largely true.
Examples: Turkish, Japanese, Latin, Ancient Greek.
Counterexamples: ?Navajo
2. Head-final languages have postpositions (instead of prepositions).
Examples: Turkish, Japanese.
Counterexamples: Latin, Ancient Greek.
3. In head-final languages, comparatives of inequality place the 'standard' before the adj. ("The dog is bigger than the cat" is rendered as " Dog cat-from big/more")
Examples: Turkish, Japanese.
Counterexamples: Latin (often), Ancient Greek (often).
4. Generally, adjectives (and genitives) come before the noun they modify.
Examples: Latin (often), Ancient Greek (often), Turkish, Japanese.
Counterexamples: ?
Counterexample to the converse: English.
5. Corollary: 'Titles' are placed after the name. Surnames are usually placed before given names.
Counterexample to the converse: Chinese (both titles and surnames).
6a. Relative clauses precede nouns in head-final languages.
Examples: Turkish, Japanese.
Counterexamples: Latin, Ancient Greek.
6b. Subordinate clauses precede the principal clause.
Examples: Turkish, Japanese, Latin (often), Ancient Greek (often).
7. The equivalent of a relative pronoun in head-final languages may be a topic marker within the relative clause.
Er, what?
8. Head-initial languages use conjunctions to introduce complements. Head-final languages may use nouns instead.
I don't think nominalisation vs. complementisation has anything to do with word-order typology, but I could be wrong. People sometimes claim that Turkish has no complementisers, but that isn't true: although
ki "that" is a borrowing from Persian, they use it all the time.
9. Infinitives are rare in head-final languages. Verbal nouns are common.
What is the difference between those?
Examples: ?
Counterexamples: Turkish, Latin, Ancient Greek, ?Japanese.
10. Head-final languages express modality and tense/aspect after verb stems.
This is the same thing as 1.
11a. The interrogative marker (if any) follows the V in head-final languages.
Examples: Turkish, Japanese.
Counterexamples: Latin, Ancient Greek.
11b. Sentence negation markers, too.
Examples: Turkish, ?Japanese
Counterexamples: Latin, Ancient Greek.
12. Head-initial languages usually do not have a passive voice.
Y'what?
Examples: ?
Counterexamples: Turkish, Japanese, Latin, Ancient Greek.
13. In head-initial languages' numerals, the word for 10 precedes the lower numeral (since it is treated as a 'standard' as in comparative constructions.)
Examples: Turkish. (I have no idea what Japanese does.)
Examples of the converse: English.
Counterexamples of the converse: Latin, French, Italian, Spanish.
------------
Can anyone supply me with more data from languages other than those four?
vlad wrote:Latin has prepositions: sub abore "under the tree", in casa "in the house", etc.
And look what happened: it switched word-orders!

It's actually been found that the most reliable indicator of word-order typology is the adpositions: they're least likely to be the "odd one out".
By the way,
casa is Spanish, and the Latin word for "house" (
domus) takes a locative.
Yours, Tim.
[i]Linguistics will become a science when linguists begin standing on one another's shoulders instead of on one another's toes.[/i]
—Stephen R. Anderson
[i]Málin eru höfuðeinkenni þjóðanna.[/i]
—Séra Tómas Sæmundsson