What is Germanic about English -- and incomplete list. Can others add things I missed?

Just a few notes:

• Some aspects of German and English that you mention may have evolved either through convergent evolution (independently), or because the daughter languages formed Sprachbund and borrowed various things from each other.

• I don't know much about the Scandinavian languages, which are important in this comparison.

Ad 1: this may be true (but was this also the case in Proto-Germanic? I'm not sure).

Ad 2: this is common in all Indo-European branches, e.g. Greek, Latin.

Ad 3: this is probably correct, although those vowels have also changed somewhat in some Germanic languages, e.g. Dutch zingen/zong/gezongen, zwemmen, zwom, gezwommen.

Ad 4: I believe the future tense in various Romance languages was formed from the infinitive and forms of habere "to have", e.g. French j'irai > Latin infinitive ire + habeo ("I have" is now j'ai in French).

Ad 5: the same Indo-European suffix is used in Latin, -or. And the Greek suffix -ôr might also be related. But is the -e- perhaps common to all Germanic languages?

Ad 6: Latin (-(i)or) and Greek (-er-) also have this Indo-European suffix, I believe. In Swedish, I believe it is more like -ar(e).

Ad 7: this may be true. Dutch has te.

Ad 8: this may also be true.

Ad 9: this may be true, although I'm not sure whether Proto-Germanic had gendered plurals (my guess would be no).

Ad 10: Greek and Latin also combine 'prepositions' (like in) with verbs in ways that change their meaning unpredictably. The placement of a 'preposition' removed from the verb, and yet syntactically and semantically connected with it, may be typically Germanic, though. Even so, especially early Greek (Homer) could also use separable verbs, where the prefixed 'preposition' could be used like an adverb after the verb. Note that all or most prepositions were probably once adverbs, in Proto-Indo-European or the like, which explains the changing positions of prepositions in the modern languages.

Ad 11: this may be true: neither Greek nor Latin likes to put the preposition after the relative pronoun.

Ad 12: this is an essential one: of the, say, 50 commonest English words, probably 90% or more are of Germanic origin.

Another essential point is the unique combination phonological laws that changed our branch of Proto-Indo-European into Proto-Germanic: English has the results of those laws in common with all other Germanic languages, even though some of those results have been mixed up by later changes. Some of those laws are themselves unique to Germanic; others are not unique but form a unique combination of laws—one that is seen in all Germanic languages and in none of the other languages.

One grammatical thing I suspect is typically Germanic (thought perhaps not unique) is the basic preferred word order [subject] [finite verb] [object]. E.g. Latin generally prefers [subject] [object] [finite verb]. In general, the Germanic languages seem to depend on word order more than Latin or Greek.

A smaller sub-thing is this theory I have: in the Germanic languages, I suspect there was inversion of subject and finite verb when the (simple) sentence began with something other than the subject. This is still the case in Dutch and German, but it is not really visible in English, except after adverbs like only and never: never have I seen..., only twenty pence did I pay...