as well as general principles "developing/opening lines" you should at least think "can my opponent mate me in 4"

or not

Ng3 a5 Ra6 Rf6 Rxf1 mate

Ng3 h5 Rh6 Rf6 Rxf1 mate.

Ba6 Bxb7 Bxa8 d4 Nc3(?) to defend against the mates and retain material advantage

g3 Bg2 Bxh1 a4 Nc3 to eliminate the knight altogether and mobilize the queenside.

I think Black has a big advantage in both lines, though I can't prove a mate.

In the first case Black has 6. e5 ed dc cb baQ Qxc1+ when at first glance it looks like White is toast: he can't mate in 7 and needs four moves to capture the Black Queen (if he doesn't capture her, it is surely mate). BUT White can play 7. Ke2 Kf3 Ne2 Nxc1 h3! (or g4!) Bxd5 Bxf7 when Black can't queen any of his pawns and probably can't mate, so the game goes on. Is there anything else Black can try?

In the second line, 6. d4 dc cb baQ a5!? Qxc1+ looks even stronger. Again White can't get away without taking the Black queen, imo (e.g. 7. Ke2 c4 c5 c6 cb baQ Qxb8+ is met by 8. Kd7 f5 fe e3 ed d1Q mating with 2 moves to spare), and if he does take the Q with e.g. 7. Ke2 Ke3 Ne2 Nc1 e5 Bxb7 Bxa8, then Black can take enough of White's pawns to make sure none of them can promote: 8. h5 h4 hg gf f1Q Rh2 Qxd2+ and wins

Yeah, allowing Black to capture all the way to the backrank and queen any pawn (a, c, d or g) is brutal in both variations. Looks like White has to play (b3, Nc3) right now AND defend against the rooks at the same time!
Maybe 5. b3 Nc3 d4 Be3 Be2 could hold the position momentarily.

Yeah, that looks like a better try. Black can still play something like 6. c5 c4 cb b2 Kd7 bxa1Q+ when I don't see a mate for White and the Q is still really hard to capture, so Black is probably still winning.

Starting with c5 is better than a5 imo because it stops White playing 7. Kd2 a4 a5 a6 a7 a8Q Qxa1, and gives more luft for the Black king.