You will need to render out those two AE compositions to video before you can bring them back into AE through dynamic link. If you are concerned with making changes, you can always replace footage in Premiere with a new render.
Dynamic Link is just not designed with your workflow -- AE doesn't open multiple projects at one time, and your workflow ends up with AE trying to open 3.
You can bring those two compositions into AE as imports. They won't be linked together (so any changes in original project will not reflect in imported version) but you would have all 4 elements in one AE project.
You have an empty loop going. After Effects cannot reference the After Effects projects already in there. Dynamic Link won't work that way.
Your best option is to render the embedded After Effects compositions that you have embedded in the Premiere Pro project.
Another option is to create titles in AE and import them into your PrPro project.