The counterop weighs less than 300 lbs. The cabinets probably weigh less than 100 lbs. This is about 400lbs spread over a floor area of almost fifteen square feet. this is less than 30 lbs per square foot.
An adult standing still is about 150 lbs on one square foot.
You should have no problem with the load regardless of the placement with regard to the joists.
First off let me quote the American Wood Council PRESCRIPTIVE RESIDENTIAL WOOD DECK CONSTRUCTION GUIDE (which I recommend looking through).
MANUFACTURED WOOD I-JOIST: Many new homes constructed with wood I-joists include 1" or thicker engineered wood products (EWP) – such
as oriented strand board (OSB) or structural composite lumber (SCL)
including laminated veneer lumber (LVL) – as band joists (or rim
boards) that can support the attachment of a deck.
However, some older homes might be constructed with band boards that
are too thin (less than 1") to support a deck. In such cases, a
free-standing deck or a full plan submission is required.
You asked:
Question 1: I assume that if these clips are still being produced that it must be code assuming proper lag screws and spacing have secured the ledger board?
Yes.
It doesn't matter how the joists have bearing, whether it is a hanger, ledger, or beam. Just use the appropriate hardware/fasteners for the application.
Question 2: If I were to cut away the masonry and lag into the 2x6
studs for the ledger support, would this be a sturdy code compliant
ledger board?
Back in the "good old days" when homes were balloon-framed they would use let-in ledgers or ribbon boards to support the floor framing (which was also nailed to the studs, though). So, it is doable, but you may need special permission or even engineer's drawings/specs for approval (might also include blocking and extra hardware). Either way, I would say it is not exactly ideal, but at least you could use structural screws like Ledgerloks or GRKs, since they are smaller diameter and self-drilling and not nearly as likely to split the studs.
(balloon-framed, ribbon-board (ledger) and fire-blocking)
And finally, if applicable, if I were to cut away the masonry to mount
a ledger board, I would be worried about water possibly penetrating
and getting behind the decorative masonry.
You would have the same worries doing the same thing when cutting out siding for a ledger. Flashing to the rescue :)
Question 3: What is the most appropriate way to prevent water from
getting behind my ledger board or the masonry?
Again, flashing is the most important part (aside from proper fastening). You have to lap the flashing properly with the building paper. Just remember the direction water flows so the surfaces have to lap the same way a shingle would. See image below for a good illustration of proper flashing. You can also read this short article describing some of the flashing material choices.
After all that, I would say your best bet is to verify your rim board thickness and do a normal ledger. The second best option is a free-standing deck.
Just be careful there is a lot of bad advice and information on the internet!
Best Answer
If you use several lag bolt of sufficient size, you probably would be OK, but that is not a preferred method.
The load will be concentrated on the threads of the lag bold and the wooden fibers holding the threads. Bolts and screws are much stronger when the load pulls perpendicular to the axis of the fastener instead of parallel to it. This then relies on the shear strength of the fastener. Basically to pull such bolt(s) out, you need enough load to cut the bolt(s) in half, which is much higher than the load needed to rip through the wood holding the threads.
If you use a 2x4 spanning mount, the same rules apply. Attaching them to the bottom of the joist is again depending on the strength of the thread in wood, not the strength of the bolt itself. Putting them over the bottom plate of the joist and lag bolting them sideways uses the shear strength and is a much stronger setup.
A 2x4 laid flat (with its 3 1/2" side running horizontal) is not its stronger configuration. It is much stronger and less prone to flex if you set it on edge (with its 1 1/2" edge horizontal). But it is hard to drill a decent size bolt hole through the 1 1/2" edge, and it weakens the piece. You probably need to lay it flat. If the span is wide and if your attachment point are not close to the joist face, consider stacking two pieces on their flat sides.
If you use that approach, you shouldn't just screw lag bolts up into the 2x4s. Instead, drill through them completely and use a conventional bolt and nut with oversize washers on the tops of the 2x4s. This spreads the load over a much larger area (several inches instead of fractions of an inch).