US Immigration from Ecuador

This short older thread (now closed to comment) contains some valuable thoughts about consulates and about co-sponsors:

We can get so wrapped up in worrying about the I-129F petition itself -- how to package it attractively, how long it's taking to process it, etc. -- that we forget crucial elements during and immediately after that phase. The linked thread rightly suggests that each of us become an "A" student of the entire immigration process. I think that it's worthwhile reading and that you'll find it to be of high value.

Feel free to comment here on what insights you've gained from reading that thread.

I came to the US with a tourist Visa, I overstayed and eventually got married with a born US citizen. We are trying to fill out the forms for my AOS. Under eligibility category should i write (C) (9)? Im filling it along with the I-485 form.

My wife is a born US citizen an we are trying to complete the I -130 form by ourselves. In this form they ask for her parent's address of residence. But her mom passed aways many years ago, should i leave it blank or write DECEASED?

Is it necessary to buy a roundtrip ticket for the flight entering the US after the interview to obtain the green card? We, of course, only want a one way but I am not sure if there is a problem checking in for the flight in Ecuador when we don't technically get the green card until going through immigrations in the US.

In your experiences do you think being ALT can have any effect on approvals?

By ALT I mean alternative having tattoos, piercings, dyed hair etc... is this something that can be discriminated against during medical exams and or consulate interviews?

Would love to hear your opinions! Thanks!