Hello Spineyro and welcome to our family, so glad you could join us and we look forward to hearing more about you and Simi.
Only by dna testing will you know for sure whether you have a male or female and it makes no matter about whether it likes one sex over the other, that is a myth.
A lot of greys do tend to be one person birds, they usually do pick a favorite but that doesn't mean that there won't be a good relationship with the other members of the household, it will just be different.
I wouldn't take her food away from her, she should have some available at all times, like her pellets that she can nibble on when she wants as some greys do eat some at night.
I don't know about the training but you will just have to find out what she likes best and save that for training purposes or maybe she could be rewarded with praise for training, that works for some.
You will find lots of useful information in our many threads so do read thru them at your leisure and do ask questions you may have and we will help you in any way we can.
I take that to be a picture of Simi in your avatar but if you have others you would share with us we would love to see them.