Am I being dumb for not using dread fighters and other online items?
I'm deep in Conquest on Hard and faring just fine without using any of the bonuses apart from the extra Boots you get for owning multiple campaigns, as Boots are too useful to do without. I actually haven't bothered with any of the Heart or Friendship Seals either, just using Master and Offspring, although that's just a habit of coming from the pre-reclassing era of FE; I like taking the standard promotion paths so my units don't have to rebuild their weapon skills from scratch.
I might play with Dread Fighters and the Ebon Wing flier, whatever it is, once I get around to Birthright and Revelation. But for my first run I am staying old-fashioned.
Is pairing the suggested way to go? I struggle with some of the harder levels and tend to never pair-up. Should I be pairing?
I'm finding that there are a number of scenarios in this game where clearing out a whole cluster of enemies (and leaving room to heal yourself up next turn) is more valuable, and perhaps easier to execute, than purely mitigating damage. Often that means I need to squeeze all the damage I can out of leaving units unpaired and adjacent, unless pairing gives enough of a boost to Spd that it grants the lead unit a double attack. There are several maps in Conquest that reward you for moving quickly and punish you for entrenching too passively. I am, however, using Pair Up and Separate every turn to move my units up the field as swiftly as I can, just as I did in Awakening and with the Rescue mechanics in older games. The extra square or two of movement you get out of this absolutely matters.
One thing pairing is quite good for is building super-tanks with Def or Res stacked to the skies, which comes in handy if you need to hold the line or bait a big threat into position. Front-line units vulnerable to attack the next turn should usually be paired to avoid the incoming bonus damage from adjacent supporting enemies.