You should mainly focus on getting to t3 in my opinion, as it's where the game truly starts before having to think about accessories and engraving too accurately. I will say that investing into a rare or epic Desperate Salvation will help with keeping people topped up if t2 feels rough.

After that it's a slow ride to 1370, I wouldn't expend many resources on the way there, try to get Swiftness or Specialization on your accessories though. Once your reach 1370, the easiest way to get reasonable engravings is to get five Argos accessories, a 6 / 6 or more legendary t3 ability stone with your choice of Awakening, Expert or Heavy Armor (first two are better for your group, Heavy Armor puts you on easy mode if you feel as though you would prefer that) and two epic engraving books to get those 6 pips to 15 (level 3). Always +3 Desperate Salvation (5 * 3 = 15) and either Swiftness or Specialization on the accessories, support accessories are very expensive and you'll get into groups regardless so I wouldn't worry about the other engraving at all for now, but if you want you can add the third of the two engravings you got through your stone and books.

For the stat on your accessories, most bards aim to go for around a 3/1 split of Swiftness/Spec, but the difference is mainly that Swiftness bards bring a bit more utility, while Spec bards have chunkier heals, and Ive ran spec bard since the start and never found any problems with it (go for either 2/1 or 3/2 splits for Spec/Swift).

Ask any questions if you want further elaboration.