@ All: Thanks for the quick, helpful input. I can see why WP is lauded for its strong community feature. Sounds like I should consider a couple of the default themes versus a few other themes as I also pick a site-builder app like BoldGrid or Elementor [as I am not a coder who is trying to DIY build a first-time site].
(1) If I build a 12-page website by adding a non-default theme (like Page Builder Framework) plus a site-builder like SiteOrigin\PageBuilder … but I keep the default themes for backup/testing, does that bloat my site in terms of too much code or front-end size … such that it will slow my TTFB loading/rendering … and thus hinder my SEO and search rankings?
(2) Is there an easy way to know if a theme is based on a framework like Headway or Thesis … to be able to keep my changes in a child-theme to preserve them against theme or core code updates?
(3) How do you all pick a theme, with so many options? i.e., besides trying to compare reviews and author support, do you just assess how many style elements you would keep versus change?
@ Jan: for questions like mine here [essentially, trying to learn a bit before starting to build], should I be posting to the “everything else” / misc. forum instead of “FixingWP”? Just curious, as I want to ‘ask the right way’.