Mg teams or snipers in buildings are better for holding infantry. Also use your engineers to build obsticals (barbed wire and tank traps). Choke points are your friend, make them where ever possible. Block as many avenues of approach to your base as possible. The ones you leave open, fortify the crap out of them, and then defend them like your daughters purity. ;)

For the companies and doctrines. Which one works best depends on your paly style. Infantry company/dfensive doctrine are for turtlers. Armoured company/blitzkrieg doctrine are for rushers. Airbourne company/terror doctrine are balanced between the two extremes.

Point capping strategy should be feul and munitions first and command points second. A building strategy doesn't really apply to the Germans. As they only get 1 bilding for each tech level they buy. The allies you should build a barracks and weapon support center first. Then the upgrade center, then a motor pool, then a tirage center, then a tank depot.