OK, here is how you launch an AGM-88 from a Mig. This ignores any aerodynamic issues but that is a "try it and see" with a war on. Wear your thousand stitch belt.
The AGM-88 is launched from the LAU-118/A Guided Missile Launcher, which is rigidly attached to the aircraft hardpoint. Undoubtedly, the Russian built hardpoints don't have the same hole patterns, but this is a mechanical problem. Some kind of adapter fitting can be built. The LAU-118 remains attached, so the key here is rigidity and strength. It has to support the aerodynamic load of the missile which can be considerable. This is a pretty solvable problem however. Consider it done.
The next real problem, and this is the really hard one, is to install a MIL-STD 1553 cable running from the hardpoint to the cockpit. This is a nightmare. If you are real, real lucky you can follow the existing control wires to the hardpoint, possibly removing them as you go. However, to do this you are undoubtedly going to have to remove riveted (on Russian planes anyway) wing and fuselage panels that are not designed to be "field replaceable". Once inside the fuselage there is no telling (without the drawings) how much stuff you have to remove to access the wiring. Possibly you may chose a different path for the wiring to minimize this effort, but that has its own challenges. Doing this work could easily take a couple of months. There is really no way around this step. You need the 1553 bus to run the LAU-118. This also assumes the Russian wiring at the hardpoint can already supply enough +28V to the LAU-118. If it can't, you are going to have to fish that wire through too.
Good view of LAU-118 https://en.wikipedia.org/wiki/AGM-88_HAR...n_F-4G.jpg
The good news is that the 1553 cable is not very large in diameter and is readily available. So are the connectors. Lets assume you got the 1553 cable into the cockpit. Now things are a bit easier. At this point it would be reasonable to assume you can use a tablet computer and a USB to 1553 converter (yes, you can buy this COTS) with appropriate software to launch the AGM-88. Creating that software could be time consuming however, and you have no way to test it. If you can get such a thing from the US (which is possible, there are maintenance aids like this available) that may be the way to go. Alternatively, assuming this is a 2 seat Mig, the GIB can hold the display in his hands with a CP-1001 under his feet. He can't eject, but his feet will be warm.
Now, if one of the Migs supplied by the formerly Warsaw pact, now NATO, countries had already upgraded their hardpoints to NATO standard, this work would have already been done on some of the Migs given to Ukraine. However, as I keep saying, AFAIK nobody did it. It may be that the engineering work to do this has been done but nobody bought it. If that is the case it is possible that such modification using said engineering data package was done in a NATO country before the plane was transferred to Ukraine. There has been enough time to do that if they started say in April/early May. This has the added advantage of not using Ukrainian assets that are urgently needed to keep their air force flying. This kind of "repair" is already going on, so it wouldn't be escalatory.
This is the scope of the problem, at least IMHO. I am pretty sure you can't duct tape the 1553 bus cable to the underside of the wing and hope it stays there. While you can replace the CP-1001 with an equivalent computer, you will need software with said computer that may or may not exist. Otherwise, you have a 780 lb paperweight.
Sidepoint: Very good info on AGM-88. Somewhat dated, but appropriate for AGM-88C/D. Predates AARGM. http://www.ausairpower.net/API-AGM-88-HARM.html
The AGM-88 is launched from the LAU-118/A Guided Missile Launcher, which is rigidly attached to the aircraft hardpoint. Undoubtedly, the Russian built hardpoints don't have the same hole patterns, but this is a mechanical problem. Some kind of adapter fitting can be built. The LAU-118 remains attached, so the key here is rigidity and strength. It has to support the aerodynamic load of the missile which can be considerable. This is a pretty solvable problem however. Consider it done.
The next real problem, and this is the really hard one, is to install a MIL-STD 1553 cable running from the hardpoint to the cockpit. This is a nightmare. If you are real, real lucky you can follow the existing control wires to the hardpoint, possibly removing them as you go. However, to do this you are undoubtedly going to have to remove riveted (on Russian planes anyway) wing and fuselage panels that are not designed to be "field replaceable". Once inside the fuselage there is no telling (without the drawings) how much stuff you have to remove to access the wiring. Possibly you may chose a different path for the wiring to minimize this effort, but that has its own challenges. Doing this work could easily take a couple of months. There is really no way around this step. You need the 1553 bus to run the LAU-118. This also assumes the Russian wiring at the hardpoint can already supply enough +28V to the LAU-118. If it can't, you are going to have to fish that wire through too.
Good view of LAU-118 https://en.wikipedia.org/wiki/AGM-88_HAR...n_F-4G.jpg
The good news is that the 1553 cable is not very large in diameter and is readily available. So are the connectors. Lets assume you got the 1553 cable into the cockpit. Now things are a bit easier. At this point it would be reasonable to assume you can use a tablet computer and a USB to 1553 converter (yes, you can buy this COTS) with appropriate software to launch the AGM-88. Creating that software could be time consuming however, and you have no way to test it. If you can get such a thing from the US (which is possible, there are maintenance aids like this available) that may be the way to go. Alternatively, assuming this is a 2 seat Mig, the GIB can hold the display in his hands with a CP-1001 under his feet. He can't eject, but his feet will be warm.
Now, if one of the Migs supplied by the formerly Warsaw pact, now NATO, countries had already upgraded their hardpoints to NATO standard, this work would have already been done on some of the Migs given to Ukraine. However, as I keep saying, AFAIK nobody did it. It may be that the engineering work to do this has been done but nobody bought it. If that is the case it is possible that such modification using said engineering data package was done in a NATO country before the plane was transferred to Ukraine. There has been enough time to do that if they started say in April/early May. This has the added advantage of not using Ukrainian assets that are urgently needed to keep their air force flying. This kind of "repair" is already going on, so it wouldn't be escalatory.
This is the scope of the problem, at least IMHO. I am pretty sure you can't duct tape the 1553 bus cable to the underside of the wing and hope it stays there. While you can replace the CP-1001 with an equivalent computer, you will need software with said computer that may or may not exist. Otherwise, you have a 780 lb paperweight.
Sidepoint: Very good info on AGM-88. Somewhat dated, but appropriate for AGM-88C/D. Predates AARGM. http://www.ausairpower.net/API-AGM-88-HARM.html