Critical point for superfluid Critical point for liquid-gas transition:

Where critical point for He3?

For He4?

Ising model lie in $Ising_3$ universality class. In which universality classes lie critical points of helium? 
 A: Solid-liquid transitions are typically first-order, as one needs to break multiple symmetries at once (translational and orientational/rotational). There are exotic scenarios where they can proceed via critical theories (such as the famous Halperin-Nelson-Young scenario in two dimensions), but for helium the transitions into the solid should be first-order.
The nature of the gas-liquid phase transitions should be the same as in ordinary classical fluids like water. There is a line of first-order transitions terminating at a critical point described by the Ising universality class. 
Finally, the entire line of phase transitions from the normal liquid to the superfluid is critical. This is because it describes the onset of a phase with spontaneously-broken $U(1)$ symmetry, and the effective field theory will be a two-component $\phi^4$ theory. This is called the XY universality class, or sometimes the critical $O(2)$ model or the $O(2)$ Wilson-Fisher fixed point. (Some sources might just call this universality class the $\lambda$-transition.) This should be the universality class for both the helium-3 and helium-4 superfluids even though the nature of the nearby phases is very different in the two cases.
Below is a figure from Chaikin and Lubensky, Principles of Condensed Matter Physics, comparing the phase diagrams with that of a classical fluid. Note that they don't zoom down far enough in temperature to see the superfluid phases.

