the bp-default theme should be fairly mobile friendly additionally there are many premium responsive themes out there that are already coded for buddypress. additionally if you are patient 1.7 will probably be out before you know it (no i can’t say when exactly but my understanding is that beta 1 is immanent) which should allow you to use buddypress with any almost theme.
The “base” group is by definition the default group displayed if you want a different group to be displayed on the registration as opposed to users profiles by default i would suggest you will end up with a lot of “blank” profiles. by putting that base group on the registration page you can encourage/enforce people to actually fill out the fields. by putting them on a secondary (or tertiary) field group you are presenting hurdles that your users must clear in order to fill out their profiles.
they come from the admin area you refer to in you your questions, they are displayed on member profile pages in tabbed layout with “Base” (unless you have modified that name) also being the default group displayed.
anything which is publicly visible is also by definition indexable. Even with no follow and no index meta information embedded on the page there is no guarantee you won’t be indexed.
sorry but i don’t know anything about that plugin. i did a quick google search on the galaxy s3 and javascript and it seems maybe javascript needs to be enabled on the handset for those features to be visible (at least with some carriers).
i much like yourself don’t have much if any programming skills but reading your post gives me two thoughts.
#1 not sure i agree with you about the child theme thing unless you are saying the people shouldn’t need to know html/css in order to customize html/css. if you are not saying that then i think the regular wp child theme doc should be fine. https://codex.wordpress.org/Child_Themes
#2 we (i use that term loosely) are actually working on a new default theme it’s called turtleshell which if I’m not mistaken is being designed as a completely fresh UI/X perspective and responsive from the ground up. i think you are more then welcome to be a part of that process, if you want more info start here: http://bpdevel.wordpress.com/
bonus the plan for 1.7 is (i believe) to make it work with any wp theme by default so maybe that this something to consider as well.
creating a gallery sounds like a wordpress thing not a buddypress thing per se. also might be helpful to send a link to your site or at least tell us what theme you are using.
