-Should I keep the body/back, and lens wrapped in lens wraps inside the case?
Don't. Wrapping the lenses or body in bags increases the risk of mould considerably, especially if like your id suggests you live by a salty sea. You can indeed use bubble wrap or have custom foam inserts designed. Don't wrap the lenses completely in bubble wrap unless for those assignments where the case might be banged around, bubble wrap traps humidity just like bags do.