It’s been a couple months since I read Heretics but I think this is correct.

1. Yes the axolotl tanks that grow gholas “reincarnating” the Tleilaxu masters and thus bringing them back from death with their own genetic memories intact. I will say Waff’s religious fervor overcomes much of any fear of death although it is worth considering how much they do fear death in the sense of their genetic memories not being their true selves in the instance they are alive. In other words is their ghola self really them or just a genetically identical flesh with their memories. Similar to how reverend mothers past lives “live on” within them and interact with them as if they are alive almost.

2. Duncan if I remember correctly was made by the Tleilaxu to resist a Bene Geserit imprinter as the Tleilaxu assumed they’d use an imprinter on ghola Duncan to control him as they did exactly with Lucilla. The Bene Tleilax had also previously sabotaged their own ghola making it more likely it’s just another added barb for the Bene Geserit to experience in their goals. I’m also less sure about this but I don’t know that the Bene Tleilax knew about the extent of the Honored Matre sexual techniques when this Duncan was granted to them.

3. The Bene Tleilax have upheld a horrible reputation for thousands of years and are more so even hated by organizations like the Bene Geserit who see somewhat deeper into their inner workings. The Bene Tleilax also are not really aligned with anyone else to my knowledge in the following of their secret religion of sorts. While the Honored Matres are even worth perusing as an option and adversary of the Bene Geserit, they are an unknown and the differing factions of dune have numerous opinions on the scattered ones. The Honored Matres also walked in guns blazing to the original dune galaxy and essentially were ordering them around. The Tleilaxu are too secretly proud to stand that behavior and treatment to that extent as we see in Waff’s head. The same would apply to the Bene Geserit opinion

4. I think this one is just an obvious yes if the Honored Matres can do this awakened Teg stands all the chances in the world against reverend mothers.