Joining late and like many of the suggestions thus made...
As for "cladding methods"...copper, or even slate are exceptional methods as they allow (when installed properly) an air layer away from the wood that promotes drying while still protecting the wood from the ravages of exposure.
An "encapsulation method" that lays directly on the wood such as modern latex paints, tarring, or plastic roof wrapping materials, very often inhibits proper drying and promotes interstitial moisture buildup and decay. A good tradtional oil finish however, tends to protect yet stay exceptionally permeable.
Weep holes, drain slots, and other such methods are very traditional and effective...if...(as suggested wisely) maintained properly and kept clear of "wee beasties" that like to live in them. An occasional inspection by annually and a reaming to insure proper clearance is necessary for them to stay functional.
By far, the best (in my view) of the suggestions is to have all these members facilitated as slanted (thereby draining) housings and a "free tenon"...soffit or tusk...that will lock the frame together better than any other jointing modality.
Yatoihozo (the Japanese form of "free spline tenon") are a broad and diverse joining method also found throughout most of Asian single plan multi directional joint unions. So the issue of assembly is not really an issue or challenge at all. Now you get the bearing strength gain of a housed joint, and the massive strengthening of a "through tenon" with wedge that allows further tightening in the future if necessary. Securing the spline in place can be a "modern method" of using a structural adhesive...or a traditional method such as Shachisen. A cotter, key, or drawing wedge can pin this joint well within the receiving timber.
The video below demonstrates aspects of this and several other "free tenon" and layout methods as well that may be helpful.