Engine/Frame bolts

[Divi Al]

Hi just joined so hoping this is the right section , first of bike is a Yamaha Diversion XJ600 S and it is a 2002 , stripping the bike back to frame for refurbishment got just about there but have struck issues. First of the bottom rear shock bolt is seized onto one of the collars , have been soaked in WD40 then AC-90 along with getting hit several times getting to the stage of using brut force any ideas. Then the second problem is the rear engine bolt again nut is loosened however the bolt feels tight , it is again soaking in wd40 and AC-90. Any tips as to get these off particularly the troublesome engine bolt. If need to can sacrifce the shock bolt as got replacement bolts coming as well replacing the shock anyway. However the engine bolt is more important , plus once i do hopefully get the engine bolt out what is the best way to remove the engine TIA