AOG
If Russia was to withdraw its forces - either back to Russia proper or those naval forces based (legally) in Sevastopol) were to return to base, then there would be no civil war.
There was no strife before the annexation bar one large and violent clash between pro- and anti- Ukrainian supporters in Simferopol.
It's important to recognise that it is largely, I'm afraid, the actions of the Russians themselves which has led to this crisis. Their intervention should not be seen as in any way an attempt to bring peace or stability to what was already a peaceful and stable place, albeit a haven for organised crime, which you may be assured it will continue to be (only probably more so)
In fact as I said on another thread, what is happening in Crimea and indeed in Eastern Ukraine, needs to be viewed in many ways as organised crime syndicates (the largest of which id the Kremlin) trying to protect their patch.
On the referendum, probably the vast majority of those who actually voted, voted in favour of independence, but a Ukrainian MP claims to have obtained information from the FSB in the Crimea that as few as 37% of the legal electorate actually voted. Not surprising, really, given that over 40% of the population could be guaranteed to support staying part of Ukraine, but this option was not available on the ballot paper.
So the "referendum" was no sort of referendum at all, even allowing for the fact that it was illegal.