1) Lady GaGa: she is THE personification of 4w3 which is just about the opposite of a 6. she is outrageous, exotic, passionate, expressive and doesn't care what anyone thinks of her
Let me say that you just don't know what you are talking about:
1) 6 and 4 are not opposite at all. They are actually "cousins" in the enneagram and frequently mistyped. Especially, sexual 6s tend strongly to be mistyped as 4, and sexual 6w7s as 4w3s Sexual 4w3, especially Sx/So, are dramatic expressive and rebellious. At the opposite, self-pres 4s tend to be mistyped as couterphobic 6. both 4 and 6 value intuition, sensitivity, creativity, they are both innovatives and attract by crisis situation and prone to sustain people who need help or to devote their life to a creative ideal.
2) The only variant of 6 that you seem to know is the 6w5 Sp/So-6w5 So/Sp wich is often likely to be a rigid follower of the rules and to respect norms and etablishment. That concern just a
little part of 6s. At the opposite, many 6s are actually rebelious and don't trust norms and etablishlent. They criticicize it and want to be independant and into their own. Their strongest will is to challenge their fears and to challenge norms and to be independent of what others people think,
3) Lady Gaga is extremist and want to challenge boundaries. But she's not elitist or aristocratic like 4w3s are. Her 4ish attitude have'nt always been her purpose in her life, it is actually very recent, from 2009 or hardly earlyer. Before that, she was a shy and casual-very normal- girl and still take to pride to be a simple girl of New York who just want to have fun despite she became a megastar. 6s are romantic also, but their romantism is less about their image, like 4, than about power. They give an existential dimension to that question and tend to idealize and romanticize powerful people. In the case of Lady Gaga, she romanticized the star system icon, and wanted to look like them in order to feel powerful and challenge her anxiety. So, she tend to be 3ish, to copy David Bowie, Christina Aguilera, Madona, Andy Wharol, etc, or 7ish to look like Grace Jones, Cher, etc. She's also inspired by some type 4 personality like Rilke or Judy Garland, and applies many of 4ish conceptions about art, because she learned and have been convinced that it is the right thing to do. Her art was very casual and normal before this. An interestin fact is that before she became blond, she was a bubbly brunette who was confound with Amy Winehouse, another 6w7 Sx/So.
4) The 4ish aspect of Lady Gaga is juste one aspect of her that she exibits. Like many people, you find her creative and original, but it is just your personal opinion, because many others think she's not creative, talented or original at all, but just an attention whore who copyed tons of others artiss before her, or just a Britney Spears clone. That she is superficial and exibitionish, and not eccentric or authentic at all, but artficial and obsessed with money and fame.
5) The truth is that she rely and want to personify a long tradition of star system icon, from Judy Garland to Lindsay Lohan is order to feel secured. As a 6, she is very focused on group and family. She says her fans are her family and her strongest concer is actually to be loyal to them but also to sustain the gay community that she is strongly commited with a heartleft conviction.
She is able to display a 4w3ish persona, but this is not her enneatype.
For Gwen Stefani, she's not melancholic at all, but optimistic and focused on popular succes. She can look 4w3 because it'w valuable to llok eccentric, but she's a 3w4.