Two tricky questions for gurus

First : My Mrs is from Ukraine and she living with me nearly 3 years being student dependent and now Tier1 PSW Dependent. can she apply ILR UK after another two years making total 5 years of residence in UK? that was first question
Second: I am living in UK for 5 years now on student + tier 1 PSW visas, If i change my nationality to Ukranian which I am eligible for; can I apply for ILR UK being a Ukranian citizan, livin in UK for 5 years... or my 5 years time to be eligible for ILR (as for Ukrainan citizen) will start from the day I will change my nationality to Ukrainan?
Thanks for your help in advance.