Hello Stevef,
We're sorry for the delayed response and inconvenience caused. In Edit PDF mode, to select Fonts list, there are no keyboard shortcuts through which you can change the fonts in a PDF.
You can type the name of the font while the Font list is open or press the first letter of the Font for example "B" from the keyboard and it will show the Fonts starting from the letter B.
You can fill Adobe wish form to include new features or modifications in the existing feature Feature Request/Bug Report Form
For the available keyboard shortcuts, you can refer to Adobe article Keyboard shortcuts, Adobe Acrobat
Feel free to update this discussion for any further assistance.
Thanks,
Anand Sri.