Yes, valet is offered at the Del on both 11/18 and 11/19.
The dress code for the welcome party on 11/18 is semi-formal beach attire. The dress code for the ceremony and reception on 11/19 is formal attire.
The weather in Coronado this time of year is usually in the 50-70s. Expect mornings and evenings to be cooler, so you might need a cardigan or cover-up. Midday is typically sunny and warmer, so you likely won't need any additional layers.