Hi, welcome from another newbie.
There is a real treasure trove of info in the build logs - great advice and experiences. (including the mistakes) If you are not in a huge hurry, I would spend 2 - 3 weeks reading build logs - seriously. At least the first 20 - 30 projects in that forum.
The other area that is especially helpful (for me) is in the electronics section on stepper and servo motors.
Like you, I am really poor at soldering, but I found a way around it - solder paste. This stuff goes on sort of like tooth paste, then you just melt it right on the board. I couldn't make a good solder joint if my life depended on it, but with solder paste, it is easy.
Plans - there are several plans and kits in the forum - some are pre-cut, so you can save a lot of time.
There are so many ways to configure a router setup, that a lot of it is just personal preference - but - perhaps consider 2 projects you would like to make now - and in the future, for yourself or a friend. This will guide you on size and accuracy needs.
I would not bother with a small router - just go for a 1/2 in collet router in the 3 - 4 hp with variable speed up front. There is not that much difference in price or cost to build, and a 1/2 in shaft makes for a much stiffer cutting tool.
Take a look at some of the commercial machines on here as well - k2, etc. Lots of good ideas for design, and often they sell critical parts to the home builder as well.
Almost forgot - 4 th axis. A common example is a stair way banister or pillar. Imagine that it has some areas that are round, spiral, and squre. The parts is mounted in sort of a 'lathe like" rotating chuck and the router moves around in x, y, z to make the right parts the right shape.