April combinations

It took really long time for me to finally write an article on the blog.
What can I do, some other priorities in other parts of my life, and one really pleasant travel to Madrid and Toledo (expect pictorial reports) deprived om writing.
In any case, everyone prefers quality over quantity, right?
Right?
All right, so due to really busy schedule in March, I could not publish monthly combinations during last month, but as a compensation, this months article will be extended.
As always, try to solve these combinations (and studies) by your own, and you are always welcome to write your answers in the comments.
Besides that, I really need to thank the readers for visiting this blog, as the last month visits  set the new record in monthly visitors (nearly 9000).
It seems that this month it will be even more readers.

This is very nice example. Black is exchange down, but he is on move and he can just win it back.
Is there something better?
If there is something better, try to find resources for White too.

In this example, White is on move (otherwise Black would just take the queen).
He/she needs to either release the tension (by exchanging on e7) or to find something forcing.
Kasparov once said that a knight on f5 (respective, black knight on f4) in most positions are worth one pawn.
In this position White has the knight on f5, but also very well placed knight on g4.
Well, I said enough.
Calculate the winning line for White.

White is on move.
Black has one extra piece, but he is badly stuck on eight rank.
Can White win additional material?
If yes, how?
Does Black has some resources?
Calculate.....

White is on move.
Calculate the consequences of:

1. Bxh7

Does this move maintenance the balance, wins or lose?

Black seems desperately lost.
Try to find very nice drawing line.
White´s idea is to transfer his king near Black´s b-pawn.
If his f-pawn is under attack White can push f5-f6.
Even if he lose that pawn and transpose to pawn ending, it is still easy winning for White (White´s plan Ke4, Bd4, Kd5 and so on...).
As I said, Black can draw this!

This is the position from the introduction.
When I do a training for my students, I usually teach them that there are 5 basic concepts in the endgames when you are fighting for a draw. These are: a fortress, reduction of material, stalemate, transposition to a theoretically known draw position, repetition of moves (perpetual).
In this example, we have the combination of two of these concepts.
White is on move, and despite that his pawn on g2 looks doomed, he has nice way to secure a draw.

In this study, White is on move, and he wants to win the game.
he has very dangerous passer on h-file, but it seems that Black can always stop it (by sacrificing his rook for it).
Is it true?