The other 2% of customer funds, held online, are covered in the event of a breach of Coinbase's online storage. Also, Coinbase holds all customer fiat currency in custodial bank accounts, on behalf of customers. So, if you have fiat currency in Coinbase, in a USD wallet, it is covered by FDIC insurance up to $250,000 (just like a "regular" bank). This protects customer assets (so long as they have been converted to fiat currency) even in the event of Coinbase becoming insolvent.
Yes. Bitcoin has not been made illegal in any country to date, although some nations restrict its use more heavily than others. Bitcoin is often associated with crime, because it can be used to make criminal transactions. However, this is true of any currency. Bitcoin is harder for authorities to trace than digital fiat transfers, but easier to trace than cash, and most criminal transactions in the world are made with fiat, not Bitcoin.
Ripple positions itself as a complement to, rather than a competitor with, Bitcoin - the site has a page dedicated to Ripple for bitcoiners. Ripple is a distributed network which means transactions occur immediately across the network - and as it is peer to peer - the network is resilient to systemic risk. Ripples aren't mined - unlike bitcoin and its peers - but each transaction destroys a small amount of XRP which adds a deflationary measure into the system.