Hello. When one becomes Orthodox from catechumen to Chrismated, is one declaring obodience to a priest in a one priest parish?
No. You're not taking a loyalty oath.
Is one also declaring (blind?) obedience to the entire Orthodox Church?
Yes although there are different levels of obedience as mentioned by others. Example, if you are unable to keep the fast due to health reasons, you can abstain; fasting isn't a strict requirement and you wouldn't be in a state of disobedience.
AiWhat if the priest at ones local parish endorse spiritual practices that vary from the priest / parish in the next city over and you have trouble understanding how to priests from the same strain of Orthodoxy have varied practices / traditions which each asserts as "right" belief and tradition but vary from each other. How is this reconciled?
Can you share the different Churches? Different Orthodox Jurisdictions have different traditions; however, the liturgy remains the same.
Most of all I want to understand the degree (total? partial? Use on owns reason and knowledge of the traditions?) when determining a plan for ones own decisions in life ?
You would have to establish your own worship pattern based on your personal comfort zone. If you like the church where you will chrismated, stick with that church. If you don't like the church, maybe you need to find another church to resume your cathecumenate.