Hi Peter,
Thank you for the pictures, lovely boat :)
The rotten wood in the bildge is quite common (in fact, I never saw an Edel 4 without this problem). Not to say it’s not a problem that needs to be tackled but, it’s common. If it’s still hard above, and it doesn’t move, what I would do is to make a small hole in the lowest possible place to let the water flow from the front cabin. This part is structural, so unless you know what you’re doing I wouldn’t replace it as long as it does its job. Or find someone with better advices than mine :)
It’s not a too big problem to have little amount of water in the boat and again it’s quite common.
Most of the time, water come from the top of the boat, it’s annoying but not critical. Unless water comes only when you’re on the water I wouldn’t suspect the keel seal first. But even in this case, when on the water, the boats moves and some water trapped somewhere else can show. This will take time to investigate, but I wouldn’t be too much concerned until large amount of water are in the boat.
To determine that, I would dry all the remaining water when the weather is dry, wait a few days to be sure remaining water don’t continue to spill from somewhere else, then remove the cover for a few days, wait for the rain (or throw a large amount of water on the deck) and see if water is back. If you can, stay in the closed boat and hunt for water drops, it’ll be faster. If so, water comes from the top, again annoying but not critical.
You can also dispose paper towel here and there in the boat and see what’s wet first (or with some flour or colored chalk, which makes it more obvious, but requires more cleaning afterwards).
There are many possible way for water to drip in the boat, but you can consider every hole, every cracks, every screw as a potential culprit 
To fix it, don’t use silicon (a real pain, don’t last long, impossible to remove, will ruin your paint jobs) but products that are more suited for boats (Sika, epoxy…).
A good practice is to clean extensively the boat first : first it’s very rewarding, then you’ll see more clearly what’s wrong.
The mast doesn’t look original but seems great (and I’d rather have a smaller mast than the opposite), as long as you have the sails designed for it, you’ll be alright.
The rudder looks like it has been modified too, not sure why (in calm water it may be more precise, I’d be cautious in more turbulent waters : the added surface may exerce additional force on the joint).
The winches on the deck, especially if it comes whith a second genoa rail… that’s not something I would have done. Maybe it has to do with the shape of your genoa, go sailing and see if you like it…
Congratulation ! Fair winds :)