Ensuring the flashing by dormers and the sealant in the valleys are good each fall before winter is critical. 

Maybe. 1/8 of a turn is not much but you are backing off the sealant.

How much is usually cost for add refrigerant and leak sealant ?

The cap just sets to the liner (poking up from the masonry) and you paint the crown sealant on.

I spent $30 on some pure pepper oil, rags, rubber bands sealant and strips of wood.

Ryan,If you can fix your moisture problem with the above mentioned sealants, I think your best bet is to patch the spall in the bottom face of the slab with concrete and then provide some sort of strapping system (steel/carbon fiber) in the short direction of the porch on either side of it.  

You could use Dry Lock water sealant too, but you have to eliminate water from standing there first and foremost.  

Assuming it's the former, depending on the extent of the leak and where the leak is, having them add sealant and then repressurize could fix everything.I like to price the actual parts (air handler, etc) on Amazon and eBay (new only), so that I have a basis for comparison when they quote me on repairs that involve replacing a unit.  

If not lexel clear sealant works in a pinch.

I really like the BRRR strategy but it's "impossible" to find sealant here.I live in South Florida, everything I see expensive and market always hot, market uber competitive.What would be the advice of an experienced investor to a newbie with a young family?