Hi,

1 & 2/ This theme supports you can change font for all your heading titles via Customize > General Options > Font for Heading Titles

To change color for h2 & h3 on single post pages, please add more this code to Customize >Custom CSS:

\
.post-entry h2, .post-entry h3, .wpb_text_column h2, .wpb_text_column h3{ color: #ff0000;  }

Change colour code ff0000 to any color code you want. You can get a color code here

To change the color for page titles, please add more this code to Customize > Custom CSS:

\
.penci-page-header h1{ color: #ff0000 }\

Change colour code ff0000 to any color code you want.

Best Regards,

PenciDesign