How far apart are the stars?
The A type star's supernova has been extremely destructive from such a small distance.
The first planet will have been destroyed, the following planetary nebula could have created a new system though.
Also, Red Giants are rather cool instead of hot, would have been a Super giant by the way.
It's an interesting system.

The white dwarf remnant will have a mass roughly that of our sun, it will be barely visible during day,
due to its size and distance.
The nebula left behind by the what is now the white dwarf will collapse into a new star in approx. 100.000 years.
Let's say it's a K star, about half the size of our sun, a low mass star.
The K star is in a close, tidally locked binary orbit with the white dwarf, which, on its turn, is in orbit with our ''sun.''

''Sun'' and white dwarf orbit each other at a distance of 31 AU (Neptune's distance is 30 AU = 4.5 billion kilometres.)

The K type star is in close orbit with the white dwarf at a distance of 1 AU = Earth-Sun distance.
The stars are in a constant gravitational tug of war, so the planets orbiting the ''Sun'' cannot be too far,
or else they'll fall prey to the white dwarf and its companion.
The max distance from which a planet can have a stable orbit around the ''Sun'' will be somewhere
around the Asteroid Belt.
After a long while, the nebula particles, radiation, and overall chaotic meteor bombardments are over.
The system is stabilizing.
During its life planet 2 met another forming planet, resulting in a binary planet system with an average distance
that of the Moon-Earth. Approx.

The perigee (closest point to each other.) is 310.000 kilometres.
The apogee is 440.000 kilometres. Kinda elliptical orbit lol.
The 3rd planet which is in the aforementioned binary system is 3/4 planet 2's mass.
The large mass creates bigger tidal differences, especially at the perigee.
The swelling oceans mix more with each other and wash up on the land.
Life has better chances and develops faster than on Earth.
Both planets harbour oceans and develop life.
The second one faster than the 3rd one.

Planet 1 was destroyed (what you think?)
The remnants of the supernova's shock wave would have wrecked it.

later (during the second protoplanetary disk) it clumbed together and accreted more
mass from the nebula's particles. It's now in a very close orbit around ''Sun''
(Hot Jupiter type planet.) It's a gas giant and has half Jupiter's mass (More than Saturn).

For explanation: The White dwarf and the K type star are in a Moon-Earth like orbit.
The 2 of them are in a large orbit with the ''Sun'' type star.
The Sun star has 3 planets, the first one is the hot gas giant.
The other 2 planets orbit around each other like a Moon-Earth system.
Together they revolve around the Sun star.

From the binary planet's view, the K star and the white dwarf appear as a red faint dot during day time.
At night, it's by far the brightest object in the night sky. Quite considerably brighter than a full moon....
Any details on rotations, orbital times, and atmospheric pressures. etc are now yours to shape (Whoever yours is.)

PS: I like this. My own story features an earth-like planet that is in a circumbinary orbit around
two stars ( a G and K type) that are in close orbit.
From the planet's view the 2 always appear close, similar to the Tatooine Sunset.