I suggest taking a step back and writing down the list of possibilities and start looking at them easiest to hardest.
Such as:
1. Visible leaks, front, rear, bottom, top of the engine. Go slowly over the engine with a flash light. Check block to intake manifold - "china rail" area. Check transmission bell housing for oil. There are oil plugs pressed into the back of the block (oil galleys & cam shaft plug), check for leakages.
2. Valve cover breathers. Do they have baffles? Pull out the PCV or hose and peer into them. Both valve covers will have breather ports.
3. Does the PCV valve work? If it rattles when you shake it, it's probably fine.
4. Check your spark plugs by removing them!! Any oily residue on your spark plugs? (could indicate bad valve stem seals or piston rings)
5. Excessive blow by...if the engine runs well and has good power, things are likely good. You could run a compression (or leak down) test to check. Compression test is pretty easy to do providing you have the tester. Test while engine is warmed up.
6. Valve stem seals. You said you get a puff of smoke on cold start. Is this blue? If it's tinged blue, then you may have a leaking valve stem seal. You could remove the valve covers and peer through the valve springs to make sure each valve has a seal. Otherwise you'd have to remove the valve springs (don't let valve drop into cylinder, or keeper into the block) to check for tears or wear.
As for intake to cylinder head gaskets. I have a hard time picturing those leaking oil. They primarily separate air & coolant. They do separate the valley from the intake runners, but the bottom part of the gasket would have to be missing to allow oil tossed up from the lifters to get ingested.
If you have coolant leaks from the intake gaskets, that's a separate matter and should be remedied asap. As for model of intake gasket, get the ones that fit your engine. The different FelPro variants have different intake/coolant hole sizes, EGR ports, etc... My personal opinion on the 1250 issues are that they're likely installation related. Either over tightened, or using sealant when one shouldn't. Perhaps the 1250 should be more tolerant, but it is what it is. If you pull your intake, make sure that the coolant holes on the gasket you use aren't too big for your engine - this could be the issue with you seeing coolant weeping from the intake.
1. I've been all over this thing before/ during/ after installing it. Coolant leaks from the front of the intake as already mentioned, specifically coming from each front corner of the 'china wall' where the intake and heads come together on each side. Slight weeping along the intake where it meets the heads on each side. More at the rear china wall, a little oil back there as well. Bell housing has a very light skim of oil at the bottom near the inspection cover (light enough to where it doesn't form a drop). Assume this is from the slight rear main leak that I've seen coming from there on the dowel plate down towards the inspection cover. That or the permatex thread sealer I used to seal the flex plate bolts are letting some oil through from the end of the crank.
2. Yes, they have baffles and good baffles at that, sheet metal plate below each grommet completely blocking oil off from being sprayed out. These are the ones I installed so I know exactly what I've got there.
3. I'll double check but it was brand new last summer, replaced the brand new that was also good that came on the engine.
4. Went through all the plugs a couple weekends ago to check and re-gap them, they all looked 'ok', not oil fouled. Ceramic were all still clean and light grey in color, some black deposits cooked on around the top of the plug and electrode, looked like from running a little rich, not necessarily oil.
5. Engine runs really strong, I checked compression on a couple of cylinders awhile back and all looked good there. Don't have the tools for a leak down test, probably should have had this done at the shop I've been working with last time it was in there and may still need to depending on what else I find.
6. Maybe a slight puff, I'd have to double check this to see if there is any color to it at all.
As far as gaskets, not sure why Blueprint would use the ones that are in there if they create leaks, but that's part of what I wanted to investigate by pulling the intake, maybe there is a better match for it with another series or brand of gasket.