A) Because you married a USC, you can be a resident alien even if you had zero physical presence so carry on with the resident alien plan of attack.
B) You are going to have to figure taxes with your specific incomes and decide which is best. You can file jointly, or she can file Married filing separately and you file nothing (as long as you earn no US income by year end). Usually jointly works out best but you should run all scenarios. When you file jointly, you must report worldwide income of both spouses. Yes, that is what you earned in the UK Jan 1 to July 4 converted to $$. You will qualify for the foreign earned income exclusion. Look up Form 2555EZ and read that.
Any investment income you earned (intest/dividends/capital gains paid to you in 2017) can not be excluded on your joint return. That is called unearned income and is taxed based on US rules. Basically if you earned $100 in interest and $8000 in dividends, then you have $8100 additional taxable income thrown into the pot with your (her) salary income. Your balances invested are not taxed, just what they earned you in the tax year. A big gain on a house sale has some exclusion allowed so generally not an issue unless you owned a castle and made a big profit off the sale.
Best thing for you to do is keep reading as you have been, and work through a tax return to see how the investments affect your bottom line. You will learn as you work through with some real numbers. There is no one answer fits all tax payers. A US tax return is very individual specific.
Lizzz got a reaction from chancecody in July 2021 AOS Filers