naturalisation application doubts before applying

Hi Guys,

I received ILR jan2018 and hopefully iam eligible to apply for citizenship this month, had some doubts before applying for the application. I would appreciate if someone could help me with this.
1) I applied for ilr in jan2016 on 10year basis but got rejected on grounds of deception regarding limited companies earning tax not cleared properly. after a couple of years and few court proceedings got my ilr granted in jan 2018 by tribunal.
Q) would home office create any problem or issue on naturalization application with respect to former ILR decision given by the tribunal
2) home office requires 10 years employment history record. I will be providing them 2009-2018 record which is clean and clear, but when I came to UK in 2006 neither nor my employer were very sure about the 20hour student rule. I had worked full time during complete mar2006- march2007 year.
Q) Can home office create a trouble on this although I will not be giving them this year information anyway?
3) what is the best way of applying for the naturalization application. is it online, NCS or through a solicitor.
Q) do u we have to submit our original passport if applying through a solicitor?
4Q) can home office reject naturalization application? if yes will the current ILR be cancelled?

I would really appreciate if I could get some right answers for these questions as I received my ILR through lot of difficulty and I don't want to take any risk at this stage.

Could you share more information regarding the refusal in the past , were you the director of limited company and did not pay the tax or had penalties and your full immigiration history before ilr would help to answer your query and how you won the appeal in court leading to you being grant of IlR as if deception could get you 10 years ban i beleive .