1. Dear Svetlana, the first thing you need to do is to apply for a Permanent Residence card. There are no income limits for this and it merely evidences the fact that you as a Lithuanian national have the right to live and work in the UK. However, you need this Permanent Residence card as proof in your subsequent citizenship application that you have been living in the UK VISA FREE for a period of one year prior to your citizenship application. here is a link to the UK Government website which explains the situation about the Permanent Residence card and which also contains a link to the application form for it https://www.gov.uk/apply-for-a-uk-residence-card/permanent-residence-card
2. One year after you have got your Permanent Residence card, you can apply for UK citizenship. Since 2006, there is no need for Lithuanian citizens to apply for Indefinite Leave to Remain. Nor is there any income limits. Nor are you dependent upon your husband as you have been living for five years in the UK. So you were badly advised in the past. There is also no need to show a EHIC card either. This is irrelevant.
3. So the answers to your questions are Q1. You apply on your own Q2 You don't have to pass an English test but you need to show proficiency in english by exhibiting your test results Q3 No Q4 You can apply.
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