1. Basics of financial regulation (google Basle 111) edit, no need, you clearly understand this.
2. Basle Ctte and international regulators including BoE and possibly a new Scottish Monetary Authority
3. Nothing - that's the point. Like any other bond they have an element of credit risk attached to them. Hence the lender of last resort (which AS assumes will be the BoE) will be taking on Scotland's credit risk. This may be better or worse that the credit risk of rUK (ST worse as a new county, but who knows over time). but either way a LoLR will not take a naked risk here. To fulfill this function they will need to have some say in Scotland's policy mix. Its very simple - there's a nice simple chart in the Scottish Analysis section of the government web site which makes this clear. See link below.
Like AS, others may try to muddy this issue with comment about my free lunch point. To be clear, in my case, the free lunch refers to the idea that you can delegate the role of LoLR but still maintain full policy independence. That is a fallcy.
On the first point, they do actually. Its how you use that policy independence that determines whether your currency is vulnerable or not. Contrary to public opinion, speculators dont attack currencies without reason or without fundamentals to justify their actions. To do so, would mean getting burnt and most are not that stupid.
Scotland has several choices to make re its preferred current arrangement. I would expect (in the event of a yes vote, however unlikely that may seem now) that this would be a staged process. That is all clear. What you cannot do in the interim is to simply mis-state the situation merely to suit your own agenda which is exactly what the book of dreams does.