Is it permissible to hold a large celebration, invite people, and wear a ring and necklace after the marriage contract (aqd al-qiran) that was conducted only in the presence of family and with a simple dinner?

If the marriage contract fulfills all conditions and pillars, then holding a wedding feast (walima) is a recommended Sunnah. As for wearing the wedding ring (dublah), it is a permissible custom, unless it is intended to imitate disbelievers in what is exclusive to them, in which case it is prohibited, due to the Prophet’s (peace be upon him) saying: "Whoever imitates a people is one of them." If the ring is made of gold, it is forbidden for men but permissible for women. If it is made of silver, it is permissible for both.