There's a reason the #4 is by far the most popular vintage plane available - it's a really great all-arounder. You won't regret owning one even if you move on to some other ones. It's super useful for all kinds of tasks around the shop and house.
You can get any rail you want and pay the difference. If you go with the standard 55", you might want to pay the extra $30 or so to get the rail that is perforated with the 32mm holes. It works with the 32mm cabinet system + router - may never need it, but not much more to get up front. At least, that's what I remember.
I agree with all the other comments. The 55 is just a lot easier to use around the shop since it's smaller/lighter. Although I do rip a fair amount of 8/4, I'm still happy with my TS55 (sometimes I flip the stock and finish from the other side which gets me a good-enough cut to finish on the tablesaw.
I agree with Huxley on his points. I own the Rikon 18" and have played with their other models - all very good bang/buck. I don't care about a brake at all - I turn it off and let is spin down while I do something else.
The Woodslicer blades from Highland Woodworking are very nice for resaw. But they don't last "forever" - but also don't cost too much.
I like the highland blades due to cost (low) and cut quality (good). They last quite awhile if you treat them correctly, but they do dull - I'm sure the carbide tipped blades last much longer. You'll have to learn your bandsaw when you first get it - practice, try stuff, figure it out. Bandsaws are way more finicky than table saws, which is why I love my Sawstop
LN aren't twice as good a saw, IMO. In terms of functionality, they are both awesome saws that'll do a fantastic job - I wouldn't say there's much difference there. So it's more a preference thing and some minor details. The LV saw are lighter weight with the polymer back (assuming you're looking at that style). LN are traditional saws and are heavier with the brass back.
I happen to prefer the LN for the looks, feel and weight. But in terms of sawing, you'll be really happy with either.
I just checked my stack of doug fir in the workshop. Pretty cool to see the moisture dropping over time. So - it's been about 6 months and I suspect it's pretty equalized at this point; may have gotten there a bit sooner, I haven't checked in 4 months The pins on the moisture meter only goes in about 1/2" or so, but I'm measuring pretty far from the end of the piece where most the moisture should be escaping "out the end grain", rather than "out the side" (through the growth rings) -- at least, that's my understanding.
I don't pay much attention to the actual readings, the moisture meter is just an OK one and I'm not calibrating it for species - although I guess it's set for Doug Fir I just check to see when the numbers stop changing.
I'm hoping to embark on the same adventure: building a workbench from douglas fir timbers. So, unfortunately I can't help you with the question, but will say that although my timbers came from 10 years of storage - it was outside storage. Since being in the shop, they have certainly dropped in moisture content quite a bit - but it's taken a few months. So - chunk them into roughly sized pieces (or good enough to get in to the shop) - and find an out-of-the-way place to store for at least a few months before getting started.
As Paul mentioned - Festool has a sander for each type of use - so it really depends. But I'd generally look at the 5" and 6" random orbital sanders for furniture and woodworking. The ROTEX have very aggressive modes, but don't handle quite as smoothly IMO (due to weight distribution). So I'd start with the ETS125 or ETS150/3
What I typically do is spray the cleaner (in your case water) through the gun before leaving it to sit. That'll clean it out enough to not clog up over those couple of hours. I'll clean the gun entirely at the end of the day.