The lateral movement of the valves in their guides is fairly important, mainly because they cannot seat well if they are not centered. (On horizontal crankshaft valve-in-head engines it is also important because oil runs down the guides into the ports, and burns.) The wear can be in the bore of the guides, or on the valve stems. The important statistic is how much clearance there is. Your valve guides appear to be replaceable, but it is usually necessary to ream the new ones after pressing them into the crankcase, so they fit the new valves correctly.
In one of the pictures of the bore it looks as if there may be a substantial ridge above where the top piston ring reaches. That would indicate bore wear. You will need to put each piston ring in turn into the top of the bore, just below the ridge, and measure the gap between the ends with feeler gauges. (You need to do this even if you use new rings: the bore is still worn even if the rings are not.) If you push each ring 1 cm down into the bore with the crown of the piston (i.e. insert the piston head-down) the rings will be at right angles to the bore, so you can get a meaningful gap measurement. Normally you also measure the bore diameter in several places with an inside micrometer, and compare this with the piston skirt measurement across the thrust faces, measured with an outside micrometer, but you probably don't have those. The piston skirt clearance can also be measured from underneath with a feeler gauge. Note it is only the clearance at the thrust faces that matters: piston skirts are diamond-turned or ground to an oval shape, with much larger clearance at right angles to the thrust faces.
That exhaust valve has not been sealing properly, and needs to be lapped, perhaps quite a bit. However first you have to resolve the stem clearance issue. The inlet valve needs lapping but has not been leaking much if at all.
Does the connecting rod size classification match the crankpin size classification? If it does, the normal procedure would be to measure the crankpin with a micrometer and compare it with the published wear limits. (Note that the pin will have worn into an oval shape, and we only care about the minimum diameter, which approximately coincides with when the piston is at top dead center. The top of the pin wears during the peak of the "hammer blow" of combustion, say about 15 - 25 degrees past TDC.) If there is wear to the crankpin, there will also be wear to the bearing shells. So, if the crankpin is worn but is within limits, in the absence of some Plastigage or an inside micrometer to measure the inside diameter of the connecting rod bearing with shells installed, it would probably be wise to replace the bearing shells. (I wouldn't replace them unless the wear pattern was worrisome, or the clearance was excessive after measuring the minimum diameter of the crankpin and the maximum diameter of the rod bearing. A big end bearing with 0.003" maximum clearance will be easily heard, and would be unacceptable even on a very old car. That doesn't necessarily make it unacceptable on a lawnmower, though.)
