Welcome to the Gauge. Your 1/144 scale is going to look out of place. You might get by with some stuff, but for the most part, no. I bought a bunch of "Speedeez" vehicles at Wal Mart a while back thinking they were close to N scale. They did not look right when placed next to anything N scale. I measured them and figured they were around 1/150 scale. I did keep a few aircraft and fire trucks since they can be larger, but the rest will be fun for my grandkids to play with when they show up.
I can't help you on your quest for military figures, but I thought I'd just welcome you anyway.