The socks are okay. Most women aren't going to actively like any of the items, though. Sneakers will be too casual for many, the pants blah (jeans would be better), the sweater (color) boring and rather unmasculine.... Maroon/burgundy would be a better choice.
The socks don't have to match the pants, but they probably should be similar. A green belt would be a bad idea.
The shirt should be bold enough that not much attention goes to the shoes. Green likely would look too matchy.
It's true that matching patterns is a likely misstep. A simple rule is to not mix two bold patterns. That's why the second combination looks much better than the third. Because in the last scenario, people would be looking at the apparel instead of the face.
Also, purple is such a bold color that it's likely to be excessive if worn in more than one item.
No. Orange is a controversial color. Some people like it, and some react badly to it.
His assessment of the forum sounds close to correct, but the truth is that few people are excited about polo shirts.
One additional entry (polo shirt that stands out)
Orvis is a go-to place for artsy shirts that aren't fashion-forward.
Look on Yoox. However, it is not worth it to buy anything without being confident it will fit close to correctly before tailoring. Therefore, limit brands to those that are available to try on locally.
Neck length can affect perceived body type, more so if only the upper body is in view. Long, think neck is associated with tall and slim; short, thick neck with short and not slim. A v-neck lengthens the neck, which makes it look thinner. A crew neck can do the opposite.