Can i play homebrew games on an sd2vita?

Yes, but you have to remove the SD2VITA every time you want to play your physical game. My recommendation is to back up your physical game and put it in. Yes, you can set up your Vita to play PSVita games from the microSD card and then have Adrenaline read and run games from the Vita memory card. As for adrenaline, it's your choice if you want to remove it from the microSD or the Vita memory card.

The saved games will also be in the sd2vita, you can save them to your Sony memory card, but if you were thinking of using sd2vita to store your games and then save the saved games to the Vita memory card, then no, that doesn't happen simultaneously. You should also buy a good SD2Vita card adapter, such as the Funturbo, which is essential for a jailbroken Vita, since it allows you to connect a standard microSD, necessary to install mods and download all your games and multimedia files. GameSD is a different add-on that allows you to use sd2vita but doesn't allow you to use your Sony memory card. It might be easier to get digital versions of your games so you don't have to plug and unplug the sd2vita adapter.

My main concern was to keep the saved files of my physical games on the Vita memory card, since the sd2vita takes up that space. Yes, you can change your license to um0 so that you can play with your SD card whenever you want to play with it. The sd2vita card changes it again, it works for me. Yes, you can continue playing games with physical cartridges on a modified PS Vita by turning off the console, removing the SD2Vita adapter and connecting the game card.