The first passage you listed (1 Peter 3) is one which is often used to impose upon women the prohibition of wearing jewelry or anything else that might be considered "outward adornment" including make-up. But if you really look at this passage you'll see that the subject of Peter's exhortation is inward —or real beauty. He's challenging women to refuse to cave in to whatever the world considers "beauty" (which is always external).
The passage goes like this:
Your beauty should not come from outward adornment, such as elaborate hairstyles and the wearing of gold jewelry or fine clothes. Rather, it should be that of your inner self, the unfading beauty of a gentle and quiet spirit, which is of great worth in God’s sight. For this is the way the holy women of the past who put their hope in God used to adorn themselves.
Rather than forbidding the wearing of jewelry and fine clothes or elaborate hairstyles for women; Peter is simply saying, "Don't let those things become the definition of beauty." Instead, he encourages women to consider the example of Sarah, whose beauty came from within—characterized by a "gentle and quiet spirit."
There is always a tendency among some groups to read the New Testament with an Old Testament mindset. They read a passage like 1 Peter 3 :3-5 and see nothing but prohibitions and rules. But what they neglect is the heart. Peter's message is meant to appeal to the heart — not a dress code!
You also said that Galatians 6:14 was used to emphasize that women ought not wear jewelry and such. That passage says:
May I never boast except in the cross of our Lord Jesus Christ, through which the world has been crucified to me, and I to the world.
The legalist assumes this passage is forbidding the possession of anything that might cause boasting. Since some boast in their riches by displaying their fine jewelry, the conclusion is made that the use of such things is worldly and must be forsaken. But what if someone owned and even wore fine jewelry but in her heart cared nothing for it. She could either take it or leave it, and jewelry for her was never a cause or temptation for boasting. Would having and wearing jewelry still be forbidden for such a person?
The legalist is forced to answer yes! And that's what's wrong with legalistic rules...they almost never take into consideration the condition of the heart. Instead they make general rules that everyone must conform to, or else be shunned. But they forget that its possible to never wear jewelry or makeup or fine clothing and still have a heart that is boastful and proud.
That's why God communicates to us repeatedly throughout the Scriptures that He is primarily concerned with our hearts — not our appearance. Man is concerned with the outside but God considers the heart. (See 1 Samuel 16:7)