Welcome back, commander.
1) If you'd like to tinker with the setups,
coriolis.io is a great site to do so without having to visit the outfitting.
2) Planetary landing suite is an extra module that doesn't steal space on your ship (nor the weight) Only if you choose to equip the SRV hangar, you'll have to sacrifice a part of your cargo hold. Hangars come in classes 2, 4 and 6 (they can fit 1, 2 and 4 buggies, respectively) and two ratings - "H" is heavier and uses less power and "G" is lighter but more power-hungry
3) Not all stars are scoopable. Only the ones from class M up. You can filter the gal map to show only those and check your travel route for longer strings of consecutive unscoopables and avoid them or prepare accordingly (Extra fuel tank or better FSD)
4) If you are going to land on the planet, be sure to have thrusters strong enough to handle it. Conda can be tricky. If you only use "D" rated thrusters to save the weight and gain jump range, avoid planets that have more than 3g. You can check that in bottom right corner of the Orbital HUD.