For Lamenters (and any
BA successor chapter), it's always officially been that you use all the units contained within the Blood Angels codex and just paint them up in the colour scheme of the successor chapter. Unfortunately, it means no vanilla marine stuff like centurions and storm talons etc.
In regards to units they would use fluffwise. Lots of veterans I would imagine and if I was doing a Lamenters army I would look up the Forgeworld rules for Malakim Phoros, the Lamenters chapter master and look to do some cool conversion work to build him.
Also, the Lamenters are known for their really unnatural bad luck, so if you ever lose a game, you can say that it is in keeping with their fluff