On gentleman's coats and waistcoats, button seem to be cloth cover wooden moulds with some type of embroidery on them. There are various types of hats available for the early 18th century. From the tri-corn to a Monmouth style knit hat it all depends upon your personal preferences. See links page for sources. It was the common practice of seamen to not wear shoes while on deck or aloft, especially when going aloft.
Correct shoes seem to be the bane of most re-enactors.
If you pardon the expression, shoes are often the Achilles' heel of an otherwise authentic kit. Shoes and buckles in the 18th Century were expensive clothing items and authentic reproductions are expensive today as well. Buckles of the early 18th C tend to be smaller than those used in the later part of the century. You do not need to have buckles though as the shoes can be closed with cloth ties. See links page for sources.