(1) The default text size within a form should still be configurable via
the General Settings / Text Font Size preference. The text on the main
pages is configurable via the device's Settings / Display / Font Size
setting. Which text do you want larger?
(2) No. The bar is the 'action bar'; on devices without menu buttons, we
need it to show so that users can access the settings from within the form
display. We haven't implemented code to detect whether the device does or
does not have a menu button, so, no, the bar cannot be hidden at this time.
(3) If you want the non-calendar date or datetime widget, specify the
'no-calendar' appearance.