steel connection question 1

I'd go with the assumption of simple support as well. In addition to bolt shear and bearing, you've got weld checks, bolt tear out, and gross and net plate section shear. I think it highly unlikely that any of those would be critical however.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

Are you in the US? my guess is not based on RHS... if you are or are not you may be familiar with AISC Ch. K HSS and Box Member Connections. They have design narratives and mode of failure checks for HSS connections (Hollow Structural Steel). The checks would be following the load path....

Member = OK
Member welded to plate = OK
Plate spanning to Bolts = OK
Plate Bearing on Bolts = OK
Plate Rupture = OK
Plate etc...
Bolts in shear/double = OK
Bolt Bearing on HSS = OK
HSS Wall Checks (yield, shear, ... ) these are the more complicated and are dependent on the shapes you select.

This is where i would start and then you will get a handle on things pretty quickly and realize what is going on. both your photos show lightly loaded connections so most of those checks are not important (engineering judgement )

Looks like you have self tapping screws into metal (steel?) beam in first photo, some type of fastener into an exterior wall assembly (known?).

I don't do glazing design much but I would approach it by finding your fastener capacity into the supporting material. For the top photo,flush-mounted, Split the shear evenly in the number of fasteners. Pinned supports.