So why do you think you have to use that slot. Simply use the lower of the two x1 slots OR use the other non reinforced lower x16 slot. Any x1, x4, x8 or x16 slot will work fine.
Sounds like they don't want to use that last x16 slot because it shares bandwidth with the 2nd M.2 slot.Again, unless you are planning to install something else in that other x16 slot, I'd use that slot for your add in USB card.
Then they may have to use the other x1 slot, IF that is the reason.
What is the model of your case? Maybe, don't USE a micro ATX board if your case supports a full size ATX board. Instead use a full size ATX board that has a bit more clearance.
I'd just get a board and a CPU that I didn't have to worry about the lane limitations while using M.2 if it was that important to me. That might mean waiting a while longer so that I can increase my budget, but that is something that is probably worth waiting for because it is never a good idea to start off on a new build by having to make concessions that run counter to what you TRULY want to get from the build.
I'm not sure why you think you NEED to install a USB add in card either. Why can't you just get a board that has an adequate number of USB ports from the start AND/OR simply add an external USB hub if you need more access for other external USB devices.
I understand being in Asia limits your options, depending on where in Asia you are, but it doesn't change the fact that good is good and not good is not good, that desirable doesn't change based on where you live, just because you live in a certain place. Sometimes if you want what you want and it's hard to get or more expensive, you simply have to bite the bullet a little harder to make that happen.
Yes, but the Tomahawk has two USB 3.2 Gen1 (Which is the same thing as USB 3.0/3.1 Gen 1) ports, and one USB 3.2 Gen 2 Type A port (Can be used by any Type A device that is USB 2.0 through USB 3.2 Gen2 including also any standard USB 3.0 devices), a USB Type C port AND has internal headers so that you can have additional USB ports at the front of your case so long as you choose a case that has front USB ports. If you need more than that, a single four port USB hub that you can purchase for around 10-20 dollars should be more than enough to expand your USB options so that you can choose ANY motherboard you wish to use. I don't even see the Mortar as being available anywhere unless you are somewhere other than the US, then maybe.
There are basically only USB 3.1 Gen 1 options for ports now as pretty much everybody has abandoned the use of the older USB 3.0 nomenclature and standards. I do not notice any difference in performance or throughput when using my front USB 3.0 ports on my case vs using those on the back directly from the motherboard. I've never noticed such a difference to be honest EXCEPT when a cheaper case was involved. Then it can be a factor because cheaper electronics including the cables going to the motherboard and the mini I/O board used for front panel connections can definitely be a factor much the same as using a cheap micro USB cable can affect phone charging rates. Same thing really.
Yup, "SuperSpeed" means 5 Gbps, equivalent to USB 3.x Gen 1.Upon checking the specs for the case it says "x1 Super speed USB 3.0" which is USB3.1 gen 1 if I'm correct?