Is there a way to create new files in Astro FM
After looking through the Help file and through Astro quite a bit, alas, I believe the answer is no. While it does allow for editing, the only option for creation is Directory (Folder) creation, as you pointed out. 

That being said, I think this would be an excellent feature, and might be worth suggesting to the developers. 

I know you said you didn't want other apps, but to show one directly with the feature...

this is X-plore File Manager