Ah - thanks folks; I really appreciate the input. Seems like a mid or UL tarptent w/freestanding tendencies may work best for the shorelines + beaches. I'm realizing I will be investing in 2 shelter systems - 1 specialized for coastal packrafting, and 1 UL tarp+insert for flexible 3-season, land-based conditions. Today I'm putting in an order for an HMG Flat Tarp; I'm still not 100% which bug insert to match it with (enough space to sit up, not just lie flat). The insert will be important since mosquitos and (possibly worse) Lyme-infested ticks will be guaranteed with warm weather.
I figure that practicing pitches w/a simple tarp and, most importantly, scouting the terrain will inform my decision about a more specialized shelter. Also, getting my confidence & comfortability w/deadman pitches will give me a sense of what I can manage on shorelines.
With feedback from the other thread specifically on SE beaches I'l be going with some UL tent. I like the idea of a mid, but with sandy, turbulent beaches and bugs being present I'll need a fully enclosed + supported shelter. I'll still have the tarp in other conditions but the beaches will need extra fortification.