Oh those are pretty nice, i did went to school in graphic design so i can help you out a bit with a bunch of technical details.
From the 4 design you made, id personnaly go with either half the second or fourth one, the composition is really classy with the large empty pale blue area, the squid and the company name. If i was you however, id play more with the text side since it feel like it doesnt do justice to the other side. Just an idea might be to replicate the octopus and the octopus clothing word on the text side but in light blue so the text can go over the octopus, you could move the logo elsewhere to allow octopus clothing to repeat itself in light blue.
Other than that, here is a few thing you would most likely need to fix if you were to go all the way through the project.
1- Dump the colored logo and make it monochromatic, the less color you have in your work, the less expensive it is to print, if i were you, i would dump the black as well and go for what is called a Pantone color, pantones are basically just a single color, in your case, it would benefit your friend wallet considering you have next to no colors outside of blue. If you pick a rather dark blue, you can reduce the opacity to get a light blue for the image side and it would allow your text to be dark blue. Assuming you work with the Adobe franchise, usually you can view them by swithing the color palette to swatches, clicking the little arrow thing and you have an army of Pantone style there, most used are Pantone solid coated and solid uncoated. However, dependin on where and what method is gonna be used to print them, you will need to design it in function of the method, some cant handle pantone so you will be force in CMYK (4 color process). RGB is a screen format only, if you design your stuff in RGB, it cannot be printed and once the technician change it to CMYK without you knowing it, you might be up for a shitty suprise when you pick up whatever you printed.
2- What most people dont know about graphic design is that you need ''bleed''. Basically everytime a color or a picture go to the border of the document, you need to make it ''bleed'' a bit by making it go outside the document, kinda like the squid in the 4th concept. The default value is 1/8 inch. Why? because when they cut down your cards, they will use a machine that send down a blade over a pile of your cards, its not 100% precise, so leaving a small bleed around it make sure you wont have any white in your color due to the machine cut.
3- That curve on the text side of the card kinda suck, it doesnt curve with grace, anyway you will need to redo it because of the bleed. It must bleed from both side and the bottom.
4- The word clothing under Octopus feel squished and frankly, the i is too close to the P, up to you to figure how to place it, you can try squeezing it under Octo and see what happen.
Think thats it for now, those are what struck me.