Bitcoin Q&A: SegWit and Transaction Malleability

What is transaction malleability? Can transaction IDs be changed? How does Segregated Witness make the Lightning Network easier to run? When will we have multi-party channel funding and channel balancing with BOLT 1.1.? Are SegWit transactions seen by old nodes as 'anyone can spend'? Is SegWit enough to improve scalability for mass adoption? Do you think we will get more privacy in the Bitcoin protocol before ossification sets in?