Create a Wordpress plugin / convert an existing Wordpress plugin

I require a Wordpress plugin for a sports club website. The plugin is to manage events and results for competitors. I have looked at the functionality of "The Events Calendar" and "The Events Calendar Pro" for the managing of the events part of the website. Not sure if it would be possible to add on to the functionality of this plugin with the ability to add/manage competitors and then assign results to each event for participating competitors? Or whether a completely new plugin would be better served to do the whole thing? I would also be looking for your advice as to how best store the information in the DB for competitors, clubs, events and results. Each event (race) may have different criteria (such as distance, type of event, finishing time or just position for competitors, etc). Also the competitors fall into different age group categories so this needs to be possible when classifying competitors. Because competitors ages are determined at the time of the event then this would need to be stored in the DB for the athlete at the time of the event. Competitors may switch clubs from one season to another, so again this data has to be stored in the DB at the time of the event they participated in. Also there may be certain events that form part of a series (look at this like a mini championship for a few weeks during the entire season), the competitors in these events would need to be able to be classified into overall positions to determine the winners of each age category at the end of the series. Points may need to be awarded for the events within the series so I need this ability as well. Like 10 points for 1st place, 8 points for 2nd place etc. Also there may be points awarded for certain parts of a race (such as a sprint, or multiple sprints), it may need to be possible to award points / multiple lots of points on this basis to competitors, e.g. Sprint 1 was won by competitor number 3 so he/she needs to be awarded 3 points, competitor number 8 came 2nd so 2 points etc. Competitors in certain events may come in a joint position if they finish with the same time, so this needs to be considered. Also in the overall standing they could be equal on points. So something like an "=" sign for competitors below the top competitor who finished with the same points. Also competitors may not finish a race, so the ability to assign a DNF or DQ status to a competitor for an event is required. Obviously results for an event need to be linked to that event in some way so if someone is viewing the event they can click a button to see the results. If you have any experience building something similar to this in the past that would be great to see? Any questions please let's discuss... James.