It's certainly not a cardinal sin to omit the leechilnes and buntlines from a model without sails. The leechlines and buntlines are used to furl the sail; the leechlines lead to the leaches (sides) of the sails, and the buntlines to the bunts (feet). If the sails were removed for any length of time, the bunt- and leachlines are too. Plenty of excellent models (without sails) don't include these ropes.
This kit's instructions (like every other plastic sailing ship kit's instructions, so far as I know) tell the modeler to complete the assembly of all the masts and yards before starting the rigging. Bad idea. It makes far more sense to "rig as you go." Step the lower masts, with the tops in place, and rig the lower standing rigging. Add the topmasts and rig the standing rigging for them (if the lower rigging somehow interferes with the fitting of the topmasts, you've done something wrong), and so on. When it comes to the yards, I find it easiest to rig them - as much as possible - secured temporarily to a dowel clamped in a vise on the workbench. You can attach all the necessary blocks, rig the footropes, and, if you like, secure all the lines that need to be secured to the yard before you get it anywhere near the model. You'll find that this method also breaks up the inevitable monotony of rigging a bit.
Your busted-loose pinrail is a standard hazard of that kit. Next time, consider two options: either glue a reinforcement piece of plastic strip or wood to the bulwark under the pinrail (the coils of rope on the pins will hide it), and/or reinforce the joint with metal pins (or pieces of piano wire).
The bottom line is that, as others have pointed out, it's your model. And the pictures show that it's a mighty impressive one. There are plenty of ways to interpret various features of a ship model - especially if the subject is one like this, which has been the subject of so much research and argument over the decades. It's clear that you have a model you can be proud of.
Good luck. You're certainly into the home stretch.
Youth, talent, hard work, and enthusiasm are no match for old age and treachery.