Perhaps you should look at a map to see how far apart Bad Kreuznach in the Pfalz and Eggerode in Westphalia (Westfalen) are. Also look for historic maps:
http://www.rootsweb.ancestry.com/~wggerman/map/index.htmhttp://www.ieg-maps.uni-mainz.de/You'll see that you're jumping the gun with your speculation that Johann Wilhelm Eckenroth b. 1707-1709 in Bad Kreuznach and Johannes Heinrich Eckroth b. 1709 in Eggerode, Westfalen, Münster [sic] were brothers.
You don't want to build your family tree on a house of cards.