Lets go! First your Loomis should be a 6'6 if it is a 783. That is okay because as a worm and jig rod it terrific. It is in the mag family so it is a great rod for worms, jigs, texas rigged creature baits anything that is a bottom contact bait. It is perfect for that purpose and yes 6.1 would be ideal, but if you fish deep the extra speed is helpful if you need to get the bait in and rapid fire it out again. I would leave that alone for those jobs. Now, I love G Loomis rods and between my wife and I we fish 6 of them (no I am not any richer than you I collected them over time). The IMX is some good graphite (3 of mine are IMX) but let me head you down another path. It sounds like you what you need is a 7 foot medium action moderate taper rod and a good reel. I suggest you look at an Irod Genesis II . The line is made up on really lite blanks, eva handles, a very comfortable reel seat with good finger contact on the blank. I fish an IRG 703CC it is called the Gabes Rip Rap Special. This rod is a composite and therefore it has a slower taper perfect for treble hook baits. It specs as a 7 foot MH moderate taper, 1/4 to 3/4 and line rating of 8 to 16. I fish all of my crankbaits and rattle trap type bait on this rod and I know it can handle a spinnerbait as well as I like a slower taper for those also. That rod will run you $155. Now find a deal on a Diawa Tatula or Diawa Fuega. The Tatula reels have a T wing system that throws a bait really well. I would definitely use that combo for everything short of a deep deep diving crankbait, but from what you already own, I doubt you would throw a DD22 type bait anyway. That Diawa Tatula retails for $150 but can easily be purchased for less than $110 shipped from one of the Amazon retailers. I have purchased 4 that way just this spring. Again I am not rich, I sold a bunch of tackle this spring and upgraded.
Now onto the grandson. There are lots of good choices for a medium spinning rod but let me give you a couple of suggestion. I just sold two St Croix premier rods and they are nice, but old type graphite and sorta expensive for that level graphite. Take a look at an Abu Garcia Vendetta 6'9' ML (do not worry about the lite rating all Abu's are a bit heavier than their ratings) 6-10 # line -1/8 to 1/2 lure rating. That retails for $80 or look at a Powell Inferno 6'10" medium. It retails for $100. For a reel he will fish for a lifetime without trouble, look at a Pflueger President in 6930 size. Man they cost $60 bucks and have 10 bearings. Between my wife and I we have 6 in different sizes. As for line, I stopped letting my wife use mono or copoly a long time ago. On spinning reels we both have come to use Berkley Original Fireline. Spool him up with either 10 pound or 14 pound green (that is their bright yellow sorta color) Now the equipment part is easy the hard part is making him ALWAYS ALWAYS ALWAYS click the bail over by hand everytime! That I can not help you with! LOL. My wife is an accomplished angler with many fish caught over 6 pounds including a 35 pound cat, 8 pound rainbow, 6 pound smallie etc. and I still have to "gently remind" her once in a while. Good Luck and let us know what you do. If I can help anymore pm me Bob