doozer

One thought for outdoor storage of tools: I have read of people storing paints outdoors in fridge/freezers rescued from garbage, and perhaps you could use something like that for your tools. If the body of it were not damaged then I expect it should seal well to keep out moisture and the fact that it is already insulated might be useful too.

Of course, a freezer could be too large for your space, but on the other hand it could act as a useful work surface/bench too (I'm thinking here of the flip-top style of freezer that are common here in Europe).

I rely on my back yard to cut down large sheets, so the rain was a real problem for me too. To allow me to continue to work outside even when raining, I made a version of an awning to cover an area of about 8ft x 12ft. I bought two pieces of robust and waterproof general purpose tarpaulin and tied them together to make one piece to cover the area. I then attached a rope and pulley to each of four points (two on the wall of the house, one on an adjacent wall, one on a shed several feet away) and these attach to the corners of the tarpaulin.

When I need to use the area, I attach each of the four ropes to a corner of the tarpaulin (for convenience I use quick-release catches for this, like rock climbers use) and raise each corner via its pulley. Once I tie the other end of each rope to a bracket on the wall, the whole thing is very secure. The pulleys on the house side are higher than those on the other/outer side to create a slope in the tarpaulin so that water runs off.

Unfortunately, on windy days the rain can still blow under the tarpaulin, but in general it works well, was inexpensive, and didn't make a big impact on the appearance of the house (important if you are renting or plan to sell up at some point). In an attempt to tackle the wind+rain, I tied a smaller piece of tarpaulin to hang at the open side, which is where the wind generally comes from, and this worked reasonably well.

The tarpaulin needs to be strong where the ropes attach to it - mine came with metal rings pressed into the edges, but I needed some extra attachment points so bought some additional rings myself (very cheap) and pressed them in place with the simple tool that was supplied with them. Also, the ropes and pulleys should obviously be weather resistant - I thought my pulleys were, but unfortunately they are not and so they have rusted. They still work, but they are just a bit ugly which could be an issue for a landlord/landlady.

Because of limited space, I too use a Festool TS55 for cutting sheet goods (and solid woods too, sometimes). It works very well. However, for a few years I made do very well with a homemade alternative - a middle-of-the-road circular saw fitted with a good blade and homemade cutting guides with sacrificial cutting table, to be precise. The quality of cut was excellent and of a very similar standard to that of the Festool. The benefits of the Festool for me are that the cutting guides are a lot lighter and more robust, so moving them around and storing them is easier and safer, and the dust extraction on the Festool saw is better than with my previous saw. Also, I like the plunge mechanism on the Festool, not least from a safety point of view. My previous setup was based on the very clever ideas in the following article:

http://www.thewoodshop.20m.com/graphics/circularsawintheshop.pdf

Good luck with your plans!