RDB

Using 1/4th is fine and won’t impact anything but there are 1/16th options.  You can type in “jig 1/16” on TW and all the results will have a 1/16th size offering.  If weight is a big concern, you can also just add a screw lock to the upper arms and attach the swimbaits to those.  When I want to go lighter, I will use 1/16th on all the arms except the bottom 2 where I use 1/8th.  The extra weight on the bottom helps ensure it tracks true.
 
Edit:  I said 1/4th but meant 1/8th…brain fart
 
Also, on the umbrella rigs like your picture, you can open them up by bending the wires out BUT I would bend the arms slightly below the head…not at the head.  If you bend from the head, they have a tendency to loosen up from the head after multiple bends.

I wouldn’t worry about line memory.  After you make your first cast with a medium diver, it will be gone...line memory and knot strength are so over obsessed about here.  Maybe people should make sure they are tying correctly, loosen up their drags, and stop cutting their tag ends even with their knots.  I can’t remember when I last had a knot fail, rarely have line memory issues and when I do, it’s when the reel has been on the shelf and disappears after a few casts, and rarely break off with any line type and I use lighter than most for everything.  This is one of those personal preference issues and the feedback is biased to that persons preference.  At the end of the day, presenting the crankbait in the desired zone is most important and your choice of line can have an impact on that..

Lot’s of manufacturers make great 1.5 sized crankbaits.  The reason I suggested a squarebill is they have better deflection qualities than other bill styles (more forgiving).

Since you are just starting, I would personally go with KVD.  If you go to Tackle Warehouse and type in KVD silent and KVD Hard Knock, you can see the 2 basic versions they sell (obviously 1 silent and 1 not).  They are reasonably priced, offer lot’s of color choices and have depth ranges from 3 to I think 10 feet.  As far as Rapala, the only one’s I can speak to are the BX Brat which comes in a 1.0 & 1.5 size (they may have a 2.0…not sure) and the DT series, which I love, but are round bills.  I would choose the depth based on the conditions you are fishing.  In a perfect world, I prefer to deflect off of something (cover or the bottom) but in Florida, vegetation may be a problem for bottom contact.  If you need shallower, you can always go with a wakebait.  Lot’s of Florida folks on here so hopefully they will correct me if I’m leading you astray.  Hope that helps.
 
Also, lipless crankbaits work well in vegetation, so that is another option I would consider.  Again, lot’s of manufacturers sell lipless cranks.

If there is 1 rod that I wouldn’t skimp on, it would be a jig rod.  I would go to the top of your price comfort range for that rod.  Most jig rods can handle a good amount of fishing abuse.  
 
So many people (including me) spend more than necessary on rods for techniques that don’t require the benefits the added dollars provide.  That is not true for jig/bottom contact rods IMO.

I’m not sure what you are referring to with Ben but like MN Fisher said, there are several toss out versions.  One is called Deeper which syncs to an iPad.  It’s about the size of a tennis ball and tossed or cast out with a rod.  I have seen the images and they look pretty good.  It is basically down imaging but you also have the ability to create contour maps.

Can’t buy on G. Loomis site.  Try someone like ***. 
Edit: Won’t accept name so Google G. Loomis and look for the site that says your G. Loomis Superstore.

The Conquest 842C is an awesome rod.  Mine snapped this fall and G. Loomis is replacing under warranty (though I am still waiting).  I am actually replacing it through a distributor with an 893C which I previously sold and now miss.  I found myself using it mostly with moving baits and though I love the rod, $700 for those applications is overkill in my opinion.  I use spinning for smaller bottom contact applications.
 
I will also add that I had mine paired with an Aldebaran (4.8 oz) and it was one sweet setup.  That rod & reel is not much heavier than your Antares by itself.

4” gummy worm weightless
Tangerine dream in clear water; sour apple in muddy.