Of course every noun has a gender, the question being which one it is. Dutch once had the typical three Indo-European genders masculine, feminine and neuter, just like German. Flemish (the variant of Dutch spoken in Belgium and part of the Netherlands) still has them today. In Old High German, people actually associated other aspects with nouns in addition to male/female/thing. E.g. they changed the gender of words such as people to indicate whether they were thinking of the word as a single entity, a group, or a bunch of individuals. As gender tends to be preserved, remnants of this system can be observed even in today's German and Flemish/Dutch.
The three genders masculine, feminine and neuter have very roughly the same frequency. With very few exceptions they also agree between Flemish and German for words that were once the same.
In Dutch, the masculine and feminine gender were merged into a single gender, called the common gender. It's about twice as common as the neuter gender.
The most important rule for memorising gender: Don't learn nouns in isolation, learn them along with the definite article. It's not harder to remember, and it gives you the full information.
There are also rules that allow you to make educated guesses regarding gender. Nouns tend to have the same gender as:
- other nouns with the same ending (e.g. nouns ending in -je are diminutives and have neuter gender)
- other nouns with similar meaning (e.g. all numbers when considered nouns have common gender, or in Flemish male gender)
- similar sounding nouns with the same meaning in other languages that have gender.
All these rules necessarily have exceptions, as they sometimes contradict each other.
I think word-initial h is not silent as a general rule. Het is a very frequently used word that is often unstressed. For these it's normal that they change as a result of sloppy pronunciation. The English cognate of het is it nowadays, which in Old English was (and in some dialects still is) hit. In Frisian, the word changed from hit to hat or et. In Old Saxon it was, and in Low German it still is, hit. In Standard German it is es. Similar loss of initial h can still be observed in him and her in English. http://www.etymonline.com/index.php?search=it
You can expect silent h at the beginning of words borrowed from French, just like in English. But apart from that I don't think it's a common phenomenon. I think it just means that the pronunciation of this particular word changed and the spelling hasn't been updated.
Kinda none, sorry to throw weird symbols in here, but the 'g' is probably /ɣ/ (which is very similar to what the guy is saying about 'loch') and it seems like dutch 'h' is /ɦ/. But all that was just an educated guess (take a look at http://en.wikipedia.org/wiki/IPA_pulmonic_consonant_chart_with_audio for recordings of how those symbols are actually pronounced)