Amazonia, Short answer is no, levers and brakes don't have to be from the same manufacturer. They do need to have pull ratios that are pretty close, however.

I used a set of Suntour GPX levers with 600 DP calipers for quite awhile on one bike until I found a set of NOS 600 levers. Maximum braking didn't change nor did the lever travel differ much with the Suntour to Shimano swap. Light braking events had better modulation, not a great deal, yet noticeable.

Brad