I would suggest you order a service manual for the 149, from Cub Cadet or from Binder Books ( http://www.binderbooks.com
), and that will get you started. The hydro problem is probably
a linkage adjustment problem, but the procedure cannot be easily described here. It is rather involved, and the service manual has pictures and a detailed discription.
The "rod with a round hole" on the rear sounds like what IH called a 3 point hitch. The upper casting with a round hole is 1 point, the other 2 are at the bottom on either side of the drawbar.
As for the 42" IH front blades, the blade itself is the same for all IH built Cub Cadets, but there are different subframes to adapt it to different models - one for an Original, one for narrow frame tractors that bolts on, one for narrow frame quick attach, one for wide frames (which the 149 is) etc. If you have one that has been adapted from another brand of tractor, I cannot tell you if it will fit other Cub Cadets or not.