With all these covers removed, can I still rotate the engine clockwise to DTC for checking each valve clearance at this instance? The chain tensioner and chain guides are still un-touched, just the cover removed.
Yes, you should have no issues barring the engine over to TDC.
[color=blue]The other question is how do I prepare the timing cover for RTV re-seal? What solvent should I use to clean the surfaces?
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Both the timing cover and mating engine block surfaces will need to be cleaned off of all RTV by using a scrapper, soft wire wheel or soft wire brush.
Acetone or brake part cleaner can be used to wipe the areas clean.