Of course there's always hydrogen
Hi Guys
Hydrogen won't burn on Venus so it'd be a perfect lifting gas. We can also make it in quantity from water, unlike helium of which there is no ready Venusian source.
Also, for high-pressure work under the clouds, a H2/O2 mix can be breathable and non-flammable (eg. 20 bar, 5% O2.)
High-temperature electronics are feasible - and have been tested by the DoD, I think - so teleoperated machines for working down on the surface should be feasible.
Finally Venus also has the same mass as Earth of atmospheric shielding against cosmic and solar radiation. Mars doesn't and won't for a very long time.
Adam