Do not try to use these cards/adapters with ML:

They won't work at all. ML's process of checking for a bootable card is incompatible with EyeFi-firmware (yes, your EyeFi-card has its own firmware). If you want to use first-gen EyeFi with a camera with ML bootflag set: Nope, it wont work at all. You have to uninstall (=remove cam's bootflag) before using such cards.
ML devs aren't able to fix this issue.
All other WiFi cards will work just fine!

Frequent issue: Trying to make an SD-card work in a CF-card slot by inserting card into an adapter. Frankly, most adapters are just crap. There are some adapters able to work with ML's method of checking for a bootable card. But most will just get your cam stalled. It is strongly recommended not to use SD-to-CF adapters with Magic Lantern. ML project does not support it and in case of failure you won't get any help.

There is no issue on ML's side using microSD-to-SD adapters.

Canon Support is adamant about using microSD-cards with adapters for full-size SD-card slot: It is a strict no-go!
For ML it doesn't make a difference: microSD-to-SD adapters do not contain any compontents but contacts and very short wiring. There is no perceivable performance drop with adapters.

Exception: Performance drop will indeed be seen if used with very, very cheaply made adapters where some data lines are simply not connected. I haven't come across such an adapter my whole life. All manufacturers I know ship their microSD-cards with an adapter and those offer a full set of data lines. To be shure do some benchmark runs with/without adapter using a cardreader and your PC. If a data line is missing performance will drop by a huge margin (25 percent and higher).

At the moment no ML supported cam does have an UHS-II slot. An UHS-II card inserted into a non-UHS-II device (as your ML camera) will run in a so called “UHS-I compatibility mode”. Performance in UHS-II and UHS-I modes are completely independent! To make it absolutely clear: A card with stellar UHS-II performance may (or not) have an unsatisfactory UHS-I performance. Examples for this:

SanDisk Extreme Pro 280MB/s 32GB UHS-II SDHC (SDSDXPB-032G): One of the first UHS-II cards.
Write rate in UHS-II mode: Up to 241 MByte/s*
Write rate in UHS-I mode: Up to 46 MByte/s*

This card doesn't even perform well in UHS-II mode and UHS-I mode is even worse.

Panasonic MicroP2 UHS-II 32GB: First UHS-II card
Read rate in UHS-II mode: Up to 275 MByte/s*
Write rate in UHS-II mode: Up to 50 MByte/s*
Write rate in UHS-I mode: Up to 38 MByte/s*

*Copyright: Data by www.cameramemoryspeed.com

Don't get me wrong, most current available UHS-II cards do perform pretty well in UHS-I compatibility mode and are only a tad slower compared to fastest UHS-I cards. But you have to take special care if you select UHS-II cards for your UHS-I camera if you go for performance. And most benchmarks available on the web don't make a difference and test UHS-II mode only.

About overclocking: ML project has no reliable data how well an UHS-II card in UHS-I-compatibility mode runs with overclocking. We simply cannot say how reliable it is or if it runs smoothly without killing your precious card.