Shortcuts in Keynote
Simple answer: no. Apple removed the PPT-like quick format bar when iWork '09 was replaced by the current versions.

Anyway, here are my workarunds/best practices:

Question 1

a) You can keep the "Arrange" tools palette open for quick access to – well – the Arrange tools.

View menu -> Show Arrange Tools



b) Most Arrange menu items /Align, Distribute) don't have keyboard shortcuts by default. But you can set custom menu shortcuts for virtually any menu item function in a Mac application. Please refer to this guide from Apple for more info:

https://support.apple.com/guide/mac-help/create-keyboard-shortcuts-for-apps-mchlp2271/mac

Question 2

Again, you can enable the Arrange Tools palette and have the Format bar switched to the Style tab so you have both toolsets available at the same time.

Personally I try to work as much as possible with custom-defined Shape Styles (I usually delete all the default styles and then create my own)