A question about the Riga Variation of the Open Ruy Lopez

After 1.e4 e5 2.Nf3 Nc6 3.Bb5 a6 4.Ba4 Nf6 5.O-O Nxe4 6.d4 exd4 7.Re1 d5 8.Nxd4 Bd6 9.Nxc6 Bxh2+ 10.Kh1 Qh4 11.Rxe4 dxe4 12.Qd8+ Qxd8 13.Nxd8 Kxd8 14.Kxh2 is the move 14..Be6, which seems to always be played, necessary?

Can Black get away with different schemes of development, such as 14..b5 and 15..f5

Does anybody have any ideas on correct play for Black in this endgame? Or where I can find more info? I think this looks playable for Black.

I think the general GM opinion on the Riga is that white is clearly better in these lines.  It certainly is playable (like anything under Masters level), but I think there are far better lines for black.  The Riga might make a good surprise weapon, but I wouldn't count on beating strong opposition in this line.   If you like materially imbalanced/strategic endgames, the Berlin Defense is similar and has a far more solid reputation.

I don't play against this line very often, but 14...Be6 seems like the most natural move.  Black wants to get rid of white's bishop pair, and with 14...Be6, Black forces white to trade lightsquare bishops (i.e, 15.Be3 b5 16.Bb3 Re8 17.Bxe6) or play 15.c3, depriving the white knight of a good devleopment square and allowing black to try and mobilize some counterplay before white's two pieces get active. 

At first glance, your plan of the immediate ...b5 with ..f5 seems dubious.  You are putting all your pawns on lightsquares and hemming in your bishop, while giving white a ready-made plan of creating a darksquare blockade on the kingside.

I'm not sure about Black's long-term plans in the line, and I'd love to hear some contributions from some other members. 

+1 to what hapahauli said.

I would add that 14 ...Be6, developing and threatening to force an exchange of Bishops, is clearly the best move.  The material distribution B+N v R+P favors the minor pieces with more material on the board.  The Rook will fare better in an ending with as much traded off as possible.  On a more open board, alone v B+N, the Rook can show his mettle, and make it difficult for the pieces to maintain good placement while avoiding awkward lateral attacks. 

The more pieces on the board, the less freedom of movement for the Rook, the more squares behind the lines will be covered, so the less he is able to make the strong threats.

So it is a reasonable general rule to say that with R+P, you prefer to head into an ending; with the pieces, prefer to start an attack in the middlegame.

maybe playable against 1400s , but honestly theres gonna be some really prepared players in all ruy lopez continuations, so why play a somewhat questionable(my opinion is that the riga is just terrible) opening then a completely playable, and perhaps better ruy lopez varation?  again i dont recommend ruy lopez for black inless you know theory like your back hand.

I've only played against the Riga once, and the game was hardly a model, but I came away with the feeling that while White may be better, the game doesn't play itself. But I do agree that 14...Be6 looks better than 14...b5. After 14...b5 15.Bb3 Bb7 16.Bf4 for example, White seems to get all his pieces into play too easily. I think Black is in for a hard time.