lemon cup

Yes and no, interplanetary missions are very hard regardless, because kerbals can easily perish in the span of 9 months from harsh radiation if you aren’t careful. With lifetime radiation turned on though, you are more likely to retire Kerbals early and replace them more frequently, which might be a strain on funds in career mode.

Yes and no, interplanetary missions are very hard regardless, because kerbals can easily perish in the span of 9 months from harsh radiation if you aren’t careful. With lifetime radiation turned on though, you are more likely to retire Kerbals early and replace them more frequently, which might be a strain on funds in career mode.

That means your kerbals will be irradiated for life. As long as they are members of your space program, all radiation they absorb will be retained and accumulate over time until they die, or are treated in a sick bay.
With lifetime radiation turned off, their radiation level resets to 0 when you recover them after completing a mission.

Not exactly sure what “partial” could mean, but KSP does recognize most controllers that interface via USB. Xbox and Playstation wired controllers, as well as the Steam controller, are compatible.
Partial could be referring to the fact that you must manually map all the controls yourself via the settings menu - nothing is mapped by default. Just a guess though!
I use an Xbox One Elite controller. Controllers have limited uses in KSP, but there is one thing they are VERY useful for - flying aircraft 

Hi there, not sure about the probe control issue but I might be able to help with the design issue! You can stack all three probes on top of each other inside one fairing with this trick.
Go to your settings menu (the one in the in-game pause menu has this option so no need to revert to main screen if you don’t want to) and turn on “Advanced Tweakables”. This presents many new options on parts’ right click menu. 
Remove one of your relay sats in such a way that clicking it’s engine picks up the entire thing (this requires that your vessel’s root part be located below your sats) and leave it to the side in the VAB for now. Now select a good size fairing and place it on top of your vessel, and make it the root part using the “Reroot” tool. Right click the fairing and enable “Interstage Nodes”. 
(Note: this may very well necessitate redesigning your launch vehicle as you may find yourself needing less boosters and cores since you will no longer be working in 3x symmetry).
Now choose a small decoupler and you’ll see you have lots of attach nodes floating in space above the fairing. Put the decoupler on the lower most node, and then grab the satellite you set aside and put it on the decoupler. Voila! Now duplicate the sat (alt+left click) and continue until you’ve stacked three together, using the remaining floating nodes. For more compact form factor, You can use the Move Tool to slide them downwards until they are nearly touching. Then it’s just a matter of building your fairing and revising the launch vehicle.
Sorry I know this is not exactly the question you asked but I know lots of people don’t know how to do this and it really comes in handy. Who knows it might somehow fix your control problem too