A thing on timelines here: The two main storylines in TLJ start at different times. The escape storyline starts a week after the events of TFA; the Ach-To storyline happens immediately after the events of TFA.
The bomber: People complained about how the bomber thing was unrealistic because there’s no gravity in space. That pedantry is inaccurate. The bombs fell due to the gravitational force of the Star Destroyer underneath the bomber. This is the same reason that Star Destroyer falls into the Death Star in ROTJ.
I read in the visual dictionary that the bombs used magnetic tech as well.
Yes, and that is unnecessary. The artificial gravity within the bomber is enough to give the bombs an initial velocity once they are released to propel them towards the target, as Mrebo already pointed it out.
Also, this obviates the need to talk about the gravity of the ship, which cannot be that significant. I wonder if someone at LFL actually saw a plothole here and came up with magnets or if they were just a cool add-on.
Look, there are plenty of plotholes and mistakes in the OT too if you don’t add EU/Wookieepedia explanations. Contrivances or not, whether it matters to you that it doesn’t make sense on its face comes down to your own choice of whether to just sit back and enjoy it.
For example:
In ANH, when the Blockade Runner’s main reactor was hit and their engines shut down, why didn’t that massive explosion on the side of the ship also knock their trajectory off course or send them spinning out of control?
Why did Luke fall sideways into a tunnel when he let go of the platform at the end of ESB?
Why did shooting an AT-AT in the neck blow it up only after it fell forward?
Why did Han and Leia only have face masks on inside the giant space slug when they assumed it was an empty asteroid with no atmosphere? And why was there sufficient gravity to walk normally on when the asteroid was smaller than our Moon?
Why was the arm that Ben Kenobi cut off in the cantina furry and clawed when one man was humanoid and the other had flippers?
Why does Shuttle Tydirium that is supposedly transporting parts and crew (by the rebels) to Endor look identical to the shuttle carrying the Emperor himself?
et al.