I have tight hip flexors and an array of postural issues that would probably relate to a tight Illopsoas but from what I have read and seen it seems that independent work of the illopsoas is unnecessary and I was wondering if exercises like these would be enough:
I don’t know why I’m even asking this is a stupid question, but thanks in advance.
this is the illopsoas btw, just above the hip flexor:
The illiopsaos is the hip flexor.
What you are missing is that the psoas minor, major and the iliacus make up the muscle group iliopsoas.
Sorry for pointing this out, but it may help your understanding of the terms a little.
No I don’t mind you pointing it out and in-fact I thank you for it because I like to learn more 
To answer the question, the link shows a very useful hip flexor stretch. Many people have a tight and weak iliopsoas. There is no reason not to train it as long as the stretches are done religiously.