If I bred the brown red to splash hens (from a blue breeding program) what would I get?
If you use the kind of splash that goes with solid black and with solid blue, you get a genetic mess. (Probably looks like a solid blue bird.) Getting reasonable lemon blues from that cross would probably take several years of breeding and selecting.
It will be faster to raise lemon blue or a "lemon splash" (or whatever they're called) from your own lemon blues to cross to the brown red. That way, you'll be hatching lots of lemon blues next year, descended from the chicks you raise this year.
Anything I could use to produce more LBs? I’m trying to get at least two breeding pens going to Build up my LB Breeding program.
You might just be stuck with one breeding pen THIS year. But if you produce some chicks this year, you can divide them up and put with various brown reds next year to make several breeding pens.
Or you could put your lemon blue hen with your brown red rooster, and buy brown red or birchen hens to put with the lemon blue rooster. That would give you two pens, and each pen would produce some lemon blue chicks, along with some brown reds. (And some weird cockerels, if you used a birchen hen--cull those cockerels.)
If you stick with just one breeding pen, you can get more total chicks (including lemon blue) by buying brown red or birchen hens to join the lemon blues. It will provide more genetic variation too, if you have chicks from several mothers.