They are going to determine a pecking order for sure, normally the smaller female will take the brunt of the damage. I went with 4 Bartlett to spread it out. I have seen 2 before without troubles (unless perhaps if both males). As long as there is rockwork to hide in. They like the ledges and swifter moving water. Not to familiar personally with Lyretail........however; most are jumpers, so make certain that you keep a top on. I have seen the Dispar and Bartlet jump out. I suspect Lyretail to be the same. I have had to fish mine out of the mega flow twice. Not so familiar with the Lyretail as I said but as a group they seem to do better in a more peaceful environment, aggressive more toward each other, even colder water, lower light.
By the looks of your equipment list, it is like a whirlpool of water movement in that tank - they should be OK with 2, if nothing to chase them. They are carnivores and like the frequent meaty feedings.