Sir Gregory would definitely have taken Winston on the crusades; that's a great way to have earned my knighthood.
Sure, why not? We were both urchins for a while, then ventured off in different directions. The last time you saw Winny, he was probably getting caught up with bandit-cultists (up to you how much you knew of that group), so meeting him again now as a paladin must be a shock!
Winston is more concerned with Good than Law, but he does make a point to follow legitimate authority. So long as we avoid doing evil and try to help others, there shouldn't be a problem there. Assuming our DM doesn't plan to make Winston fall for consorting with anti-establishment types.