I can only answer the second question, with regards to the Didache. The early church fathers did indeed respect the Didache, and I don't know why they shouldn't. Read it - it's completely orthodox and dates very early. It should only take you two minutes to read, as it's very short.
-----Added 9/30/2009 at 05:14:37 EST----- Didache. The Teaching of the Twelve Apostles (translation Roberts-Donaldson). Anyone who hasn't read the Didache before should do so, since it's very, very short and is one of the earliest church documents preserved. It provides good evidence for the apostolic origin of worship on the Lord's Day, modes of baptism, etc. Enjoy!
-----Added 9/30/2009 at 05:18:55 EST-----
If you are asking whether the early fathers regarded the Didache as canon, I'm pretty sure they did not. St. Ireneaus of Lyons, for instance, in the second century listed his idea of what should be in the canon, and it was almost exactly the canon that was eventually ruled on at the council of Nicea (i.e. the canon we still use today). The Didache was definitely not on his list. So it's definitely NOT Scripture, but is a very important early church writing nonetheless (just as Ireneaus's writings are). Hope that helps.