There may be similarities, but UKIP and SNP do not want the same thing(s)!
UKIP want not only a 'Brussels free' UK, but something that borders on Ethnic cleansing' 
SNP may want a Scotland that is in Europe, but why you should assume that they would 'knuckle under' in the same namby-pamby way of the Westminster government, I don't know. I can only imagine it is because you have no better understanding of the Scottish psyche than Westminster does.
As for uncontrolled imigration - if imigrants don't want to come to Scotland as part of the UK then why would they want to come to Scotland that's NOT part of the UK? And don't say it's because a UK that's not in Europe won't let them in, but a Scotland that's in Europe will, 'cos that won't wash. You have no better idea than the next man what sort of terms an independent Scotland might negotiate. It may come as a surprise to you, but there are areas in Scotland where imigration IS an issue!