If they're related and almost never change, then why aren't they going into the BE anyway? The fact that they are 'lookup' tables for things that don't change (like a status value for something) isn't a good reason for keeping them local, IMHO. The only type of tables I can think of (at the moment) that I'd keep in an FE is temp.
If I need to provide a user specific temporary transaction, that table likely goes into the FE, otherwise I have to distinguish between one user and another in the BE lest one wipe out data that someone else is working on.
The more we hear silence, the more we begin to think about our value in this universe.
Paraphrase of Professor Brian Cox.