So if I'm not interested in doing the full marathon I shouldn't worry about the January weekend but the other weekends are good to go, correct? Do you prefer one over the other (not the marathon)?
The half during marathon weekend and the princess half are the same course. You go from Epcot parking lot through the TTC, then to Magic Kingdom. You spend about a mile in MK, then head back to Epcot via the roads that go past the GF and the Poly. You run through just a sliver of Epcot and finish in the parking lot.
Star Wars and wine & dine halfs are the same course as each other. For these you start in the MK parking lot, go to the AK, then through a little bit of MGM (you enter at ToT and exit near the front of the park). Then you go to Epcot and run around the world showcase before finishing in the Epcot parking lot.
Marathon Weekend half/ princess half pros:
Weather in January is USUALLY better (although this hasn't necessarily been the case of late - marathon weekend can be cold and princess the last two years has been hot).
You run down main street and through MK (these are the only two halfs that do this - the marathon does this too).
Marathon Weekend half/ princess half cons:
Potential for weird weather (Jan and Feb in FL is unpredicable)
Lots of highway miles
Cone Alley
Star Wars and Wine & Dine pros:
You run through 3 different parks
Wine & Dine has the after party on Sunday
Wine and Dine is during the food and wine fest (great time to come)
Two unique themes
Star Wars and Wine & Dine cons:
April (Star Wars) in Florida is hot.
April (Star Wars) is crowded (spring break)
Hope this helps!