I disagree with you about Crimea, Donetsk and Luhansk, they've always wanted to be Russian and held referendums won by huge majorities which Ukraine considered illegal and never recognised.
As others have said the Russian backed separatist referendums in 2014 cannot be taken seriously. Various surveys in 2014 in eastern Ukraine paint a different picture to your claim above:
“A poll released by the Kiev Institute of Sociology, with data gathered from 8–16 April, 41.1% of people in Donetsk were for decentralisation of Ukraine with powers transferred to regions, while letting it remain a unified state, 38.4% for changing Ukraine into federation, 27.5% were in favour of secession from Ukraine to join the Russian Federation, and only 10.6% supported current unitary structure without changes.[18]
“According to a survey conducted by Pew Research Centre from 5–23 April, 18% of eastern Ukrainians were in favour of secession, while 70% wished to remain part of a united Ukraine.[
“Another poll, taken by the Donetsk Institute for Social Research and Political Analysis, found that 18.6% of those polled in the region opposed changes to the government structure, 47% favoured federalisation, or at least more economic independence from Kyiv, 27% wanted to join Russia in some form, and 5% wanted to become an independent state.”