Some more duplicates removed in the sprite set.

You can flip the "longer" half of something that has an odd number of pixels, and overlap the two halfs by one pixel.

Since that HUD stuff is in the sprite set, remember about the eight sprites per scanline limitation.
Also, in the case that you do use sprites, you don't need two tiles in the spriteset for this bar:

Since sprites don't have to be aligned to any grid, you can just put multiples next to each other, whereas doing so with tiles would leave space between them. Having the extra tile in the sprite set does cut the number of sprites needed to display it on a horizontal line in half, though.
Basically, you have four choices for the HUD:
1. Keep it entirely in the backgroundset with the level.
2. Have the HUD entirely below the playfield, and use a separate set of background tiles for the HUD/playfield.
3. Use sprites, but make sure to never have more than 8 on a scanline if you don't want it to flicker.
4. A mix.
1. is a simplest choice. Keep in mind you can have many sets for different rooms or whatever, it's not like you're forced to use the same 256 tiles throughout your game. Yes, having the HUD as part of the background set would take up some space on every set, but it's not too limiting for the type of game this is looking like.
2. is cool, and you'd need the HUD entirely below the level if you wanted to scroll anyway.
3. is okay if you don't need to display a lot of information. But it looks like your game needs a lot of info on screen.
4. could be awesome with 2 or 1. You could keep the icons in the spriteset (coin, gun etc.), since they need to be there anyway. They'll be in the level as collectibles sometimes. You could keep other parts of the HUD there too. As long as you never have have more than 8 on a scanline, you're fine. I wouldn't do the numbers as sprites. You've got 8 on a line doing that right off the bat.