If we pushed Mercury out of orbit for a close fly by of Venus in order to put Mercury in roughly Venus's orbit while flinging Venus to swing by Mars. Which will pull Mars's orbit a little closer to the Sun, after restabilizing with asteroid fly bys to recreate a more circular orbit, while sending Venus to Jupiter. Where Venus exchanges orbits with Callisto and sends Callisto back to Mars to get captured as a moon.
Now add volatiles to Mercury, measure how much more sunlight and dynamo/magnetic field Mars has, check Callisto for volatiles released during new placement and also more sunlight below the snow line, and wait for Venus to cool down and stabilize at Earth like temperatures.
Jumping past the extreme difficulties of pushing Mercury out of orbit, are there any issues making this scenario infeasible and would it make all affected bodies habitable for life, with more energy for the oceans underneath Callisto's ice, a larger magnetic field for Mars, Mercury, Callisto and possibly Venus, closer to Earth like temperatures for all bodies involved vs. their previous temperatures, closer to Earth like atmospheric pressure (except probably Venus), etc.