1.) How do i change the header bar to remove the Voyager Title and the flower picture?
Voyager Title - You can change to logo image from backend > extension > template > edit voyager default template > upload logo image
https://take.ms/yMZp2
Flower picture - it seems like that is Joomla default custom module display under position-3 if I am not wrong, you can disable this module from your site backend > extension > module > filter the type to 'custom'
https://www.screencast.com/t/znhFCab6E > need to find which module is display that flower image.
2.) Can I customize the font for the entire template?
Currently we do not have setting for that. but you can add you custom css under this file
JoomlaFolder/templates/voyager/assets/css/custom.css
3.) Can I remove or edit the Navigation at the top of the blog? It does not flow well with the rest of my website.
Do you mean that breadcrumb section
https://take.ms/hxzcp
If yes, you can disable it from your site backend > extension > module > filter the type to 'breadcrumb' > choose the module and disable it.
4.) I want to replace the frontpage picture on the left with a text image that I can upload - something like 'welcome to the Fish Fixe Kitchen - see what we are cooking" and I always want that text to display.
Is it possible for you provide us some screenshot which part you would like to make the changes?
Because I am not sure which part you would like to modify it, perhaps you can check my screenshot here
https://take.ms/JqHai , and see whether you mean the content area should show the text instead of the image right?