I have been manufacturing PMMC meters for nearly 50 years.
In the end you have listed types of permanent magnets. But you have not given the details of which type is useful In professionally made PMMC meters. Mostly only Alnico magnets are used. Very coarse instrument such as battery charging / discharging indicators may use Strontium Iron ( Ferrite Magnets ). The main problem with ferrites is low magnetic flux density and much higher temp co-efficient. So 10 deg change in ambient temp. can degrade accuracy by 2 %. Neodymium-Iron-Boron magnets are very strong and very good mechanically, but temperature co-efficient is again a discouraging factor. Samarium Cobalt is a very good candidate w.r.t. temperature co-efficient, but since it is hard and brittle, the chances of magnet getting destroyed accidentally are high and no manufacturer can take responsibility for a fragile product. Hope this information will be useful to the readers of your post. Cost is a minor factor except in the case of ferrites which are very cheap. The Neodymium-Iron-Boron and Samarium Cobalt are expensive, but size can be reduced since they are capable of much higher magnetic flux densities compared to Alnico Magnets. The other limitations of both types are as given above.

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The pointer rests at zero because the current in coil a is relatively large.