When have we ever seen a Malfoy duel successfully? CoS he cast a spell that was (Assumably) told to him by Snape. He can't kill Dumbledore, and the only time I remember him in a combat situation is when he knocks Harry out under the invisibility cloak.

 

If you look at what I quoted, you'd realise I was referring to the "Family Magic" in Only Enemies.

 

See my most recent chapter of Renegade Cause for a Malfoy who does duel quite well - at least for a bit.

On the topic of 'family' magics, it's an interesting plot idea - but one I've seen thoroughly abused by Harry's use of the Black 'family library' to get Dark magic and become uber-awesome. Best use of it that I've found was in those family tapestries, automatically updating themselves via a form of family blood magic - seen that in a few fics, and I think I might have used it myself at one point.

 

Could be, but when one of your brothers is a curse breaker and the other is a dragon tamer, coming across rare and valuable objects seems a bit less implausible.

EDIT: Holy shit, over 3000 posts O_O.

 

A wand costs 7 galleons. The raw materials can't be that valuable.

 

I think making a wand is a process akin to painting a portrait: you could try to do it, but best to leave it to the master if you want a beautiful result.
Ollivander is a master at wand making, has decades of experience, and could make wands on demand for specific person, such as the wand he made specifically for Pettigrew in DH.