Superstitions are in all cultures. It largely depends on whether you believe them or not. No point asking others since everyone has different point of view. 

Have you encounter any of those, then?

Well, for wedding superstitions, there are plenty. Difficult to talk about all since different dialect has slight variation of superstitions...  I've been to few weddings, but I think basically it's more of respecting the host by dressing appropriately etc.  You know the drill. 

I think so... different dialect, different pantang... haha... actually I only know a little of my own one...    we share share over coffee? 

there are a lot of superstition for all occasion, it's up to individual to believe it or not.

I know a real case, not related to wedding but pregnancy.

My mother is a baby sitter, last year she take care of one baby, with some complication. He's born with imperforate anus (without butt hole), have to under-go colostomy operation to pass stool. Doctor also found that he got hole in heart, more operations for the baby to fix his condition.

After some questioning, the parent admitted to fix some water pipe while the wife is pregnant and around the house, which is a taboo to the Chinese. Wife also mentioned she don't know any taboo, no one to teach her that.

As for your own customary, the Chinese belief that there should only be one auspicious event at one time. If you and your friend just getting married within the same period, they believe the luck will compete and possibly cancel each other out. Other words, no luck for both parties.

I am not aware different dialects had different kind of taboo but what, it is advisable not to attend any wedding or funeral during pregnancy as pregnancy luck is higher than both functions. Funeral, most will avoid (understandable) but as for wedding, you are considered overshadowing the married couple's luck.