Using surround speakers as fronts is OK, but not ideal.
Unlike true fronts, surround speakers are not designed with a good frequency bandwidth in mind... well, at least this is not their priority because surround channels are rarely called upon to play a full bandwidth. More often than not, they are designed to be small and inconspicuous first. You will most likely compromise bass and treble extension, and some power handling.
For a 5k budget, you gan get a bnew pair of Diamond 9.1's, or a 2nd hand pair of speakers.