Yes there is a very good strategy with all levels of difficulty for this level just get on top of the buildings in the always use the grenades plasma/sticky ones are very helpful only come down of a building when you absolutely have to {this is for high difficulty}.
For the whaterhowg always face enemies with it front Armour will absorb hits.
Yeah I know that grenades work acceptably well wit Hard difficulty. Jst that in Legendary for this part as its too open they are easily able to outrun it. For round about everywhere else I've found atleast 1 weak point. Jst this level, specifically this part is hard to get as most of the hard places, the covenents are way too spread ou,+ they come aftr u(so no sniping them off easily frm far (thats specifically for this part),+not many jump offs,+ area too wide..
Also wen u r ontop of the building frm the 3rd wave onwards they(Elites specially) keep comin from the two sides at the same time, so motion tracker not that useful. UNSC grenades are good bt that too there's jst 4 more, and none near the life-pod....