With my 4+ years of experience in web and mobile development, I believe I have the acumen necessary to bring your Minecraft project to life. Specifically, I have expertise in backend development using technologies that include Node.js and PHP, which are core to developing Minecraft plugins. My database configuration prowess extends to MySQL, PostgreSQL, and MongoDB - three options that could best fit your project needs as per I’ve understood so far.
Given the Plot Management system you're looking for, let me assure you that claim, rename, add player/owner to plot functionalities are well within my field of expertise. Moreover, based on your requirement for a unique "item" feature not obtainable in the survival mode, my skill-set would empower me to design and implement that successfully. Moving on, incorporating flight restrictions and plot protection safeguards are also tasks of utmost importance to me. Abedding such restrictions securely into your server would be of top most priority to make sure your server admin and players remain happy.
Finally turning our attention to In-Game Economy system; enacting and managing an in-game currency is standard territory for me.