Avi K, it is a common practice to say to be a melitz yosher.
There are two possible ways to look at this without having to resort to “doresh el hamesim” issues:
1. We are asking HKBH that so and so should be a melitz yosher. In other words, we’re not directly asking the dead to do anything for us – we’re asking HKBH to cause them to intercede and pray for us.
2. We’re not praying to the dead to be a melitz yosher, we’re just hoping that they are — much as I may express hope that the weather is good tomorrow without actually asking KHBH to make the weather fine tomorrow.
The Wolf