The danger, as you probably know, in lead paint is not so much a large one-time exposure, but accumulation in the body over time. That is, your body has no mechanism to remove it or most heavy metals, it builds up in you over time. Adults can tolerate a fair amount of this but young children are much more susceptable to developmental problems due to lead. Some are subtle.
If the company is telling you there is no problem, take it with a grain of salt unless they have recently retested older batches themselves. Do you think Mattel didn't think the toys it is now recalling were safe when they sold them? Do you think that if they don't already have a recall out they are going to say "Oh yeah, we don't really know, let's look into it." You do realize that all those toys originally called safe were "inspected and tested" it's just the system was corrupt, they lied when they said they met standards.
You might also want to consider the comment they are for 12 years old and older. Is there a different lead level standard for these mini than if they were meant for 2 year olds? Probably so. The danger is of course the 3 year old in your house will want to handle and play with these minis, they may not wash there hands really well every time after doing so, and hence paint traces that get on there hands get conveyed into their mouth eventually.
Also realize that lead level standards are not bassed on assuming that minis are the only source of lead exposure to your child. There are other sources, soil still from the days of leaded gasoline and lead house paint, solder in pipes, electronics etc. Again, you don't need direct contact, all these sources release lead that finds its way into the home and other environments your children do come in contact with. You really don't need another lead source in your home when there is no need for lead in paint except to make extra money.
