BTC Lightning Network Can someone please give me some insight as to when LN will be fully operational on the bitcoin network. 

Additionally, as outlined in the 2008 Nakamoto whitepaper, the solution to the double-spend problem is clearly addressed and solved, however, given that with LN supposedly 'Billions of transactions per second' may happen off-chain, then what are the implications for how the double-spend problem is addressed?.

This is presumably handled in the software layer, under the knowledge that people must firstly stake a quantity of bitcoin in order to support the electronic IOU's.

If the above is correct, which it may not be (please correct me if I am wrong), then doesn't LN essentially become almost in a sense a 'Bitcoin backed' new cryptocurrency?
what are the implications for how the double-spend problem is addressed?


The solution to the double spend problem does not change.  Participants of the lighting network hold valid transactions for actual bitcoin.  Because bitcoin cannot be double spent, the lightning network doesn't have to solve this problem.


  This is presumably handled in the software layer, under the knowledge that people must firstly stake a quantity of bitcoin in order to support the electronic IOU's.


Despite the fact that the transactions haven't been broadcast, I wouldn't consider money on the lightning network to be just an IOU.  While it is still unsettled, it's more complete of a transaction than what we typically think of as an IOU.  The smart contacts, themselves, make the exchange on the lightning network effectively irreversible.


  doesn't LN essentially become almost in a sense a 'Bitcoin backed' new cryptocurrency?


No.  If that was true, then credit card transactions would be a separate dollar-backed currency.  Lightning is a method of exchanging bitcoin.  That doesn't mean it's a new currency, just a means of moving money.