There's one problem with all 3 requests: space.
1. Pedigree: vertical space on a paper is limited. If I add one row of text for each box, it won't fit anymore. That's the reason for the choice between the two extra lines, not at the same time. The printed pedigrees could use some extra attention, maybe reduce some font sizes, the header size, or better margins/calculations in general. But it's a messy job. The plan is to drop this way of generating pedigrees anyway. Replacing it by a pedigree designer, where you can drag and drop different elements (header/address/pigeon details/separators/pedigree boxes/...) in place and edit their attributes (font/font size/font colour/line colour/...). It's a lot of work and I only have some basic mockups ready.
I will add loft as a 3rd choice though.
2. Pigeon sub-totals & 3. Extra details: There are still too many low-end laptops around with low screen resolutions. At the moment the interface just barely fits on a 1366x768 (if I'm correct) without too much scrolling around. Adding extra sub-totals would add another horizontal scrollbar and the extra fields on the right an extra vertical one. It's a bit of a trade off, on higher resolutions there's room to spare. This might be something for in the future to optimise.
2. Pigeon sub-totals: there are however some extra statistics available if you go to Help=>Information. A bit tucked away, but it has the numbers you mentioned. It's easy to add more here and perhaps find a better place in the menu.
3. Extra details: I had something similar in mind for some time as well. My idea was to add a new tab at the bottom, with (like you mentioned) a textbox for notes/comments. Maybe even a star rating system for different pigeon features like eye/wing/health/strength/breeding... Also the hatch date, nestbox and nest mate could be here (from the other topic).