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Hi,
1, LM8UU will always have some reasonable friction. You will have to grease them for sure. Yet if it is still too different from four bearings on one rod, than something is probably misaligned. Check if the precision rods are going straight and the frog is sitting well on the bearings. But don't worry too much about it. The motors are strong enough to overcome the friction.
2, I suppose you are referring to these measurements:
197mm ... http://reprap.org/wiki/File:ToyREP-27-Distance_Between_Front_And_Rear_Frame.jpg
113mm ... http://reprap.org/wiki/File:ToyREP-38-Adjusting_Y_Frame_Distance.jpg
47mm ... http://reprap.org/wiki/File:ToyREP-39-Space_For_Arduino.jpg
The distance between inner flat surfaces of legs is supposed to be 197mm. This distance can be tightened so you have a rigid and square (perpendicular) Y frame. Then you will insert RAMPS with Arduino and push the Y frame toward Z motor mounts so the electronics is fixed in grooves between Rear Y Frame and Bottom Z Frame (PSU mounts). For this you will have to loosen nuts around Z motor mounts, move the Z frame and tighten them it on correct position. When you will do this you will get ca. 47mm distance between inner flat surface of Rear Y frame legs and Z motor mounts and 113mm between Front Y Frame and Z motor mounts. These two measurements are there only for reference to make sure Y Frame is perpendicular to Z Frame - this can be also checked by steel square, but you will have hard time to squeeze it somewhere.