Freezing lasagne made with previously frozen meat
Broadly this is OK.

By broadly, I mean a couple of things. First, I'm assuming you are cooking the meat very thoroughly. That both means for long enough time to be completely thorough and hitting high enough temperatures to kill the main nasties off. Second, it naturally assumes you observe good practice with regard to not letting it sit for long periods, not co-mingling uncooked and cooked meet, yada-yada-yada.

I do what you're describing lots of the time myself incidentally, and have done for years without incident.

Of course, as I'm sure you know, one thing that is certainly a really bad idea is to freeze defrosted meat without cooking it.