I was happy to see the Daiwa BG in there. That would be my pick. I run 3 of the 2500 size and a BG MQ 4000 for kayak fishing. I have a BG 4000 for my 9’ surf rod as well. I have not personally used Kastking. A lot of folks like them for the price, but I’ve been fishing long enough to know to stick to trusted brands. Penn, Shimano, and Daiwa are all I buy. Penn, in my opinion, is currently junk UNLESS you get some of their higher end stuff. Stay away from the Battle line. I’ve had a Battle II, a Conflict, and a Fierce. They all gave me problems. A Penn Spinfisher and Slammer I have are great. Generally I prefer Shimano to Daiwa, but Daiwa gets you more line capacity for reels of the same caliber. My BGs have been workhorses, but every reel a) requires a freshwater rinse after each trip b) will require a periodic teardown to clean/lube (1 year for me and I fish a bit) and c) will break on you. Usually it’s the instant anti reverse (clutch) bearing that goes in my experience. A trusted, name brand reel will have parts readily available. I have gone through so many Shimano clutch bearings that I now order them in multiples.
The kind of fishing you’re looking at will dictate the size. I like a 9-10’ spinning rod with a 4000 reel. It van handle most everything. A very big drum or a shark would smoke it.
As far as bait feeder option, I am unfamiliar unless that’s like the old Shimano Baitrunner reels and are designed for live bait fishing with live fish as the bait. I just put the ones I’m not holding in a spike and loosen the drag so that a fish can run a bit while I get to the rod… remember to tighten the drag before you go to set the hook!
On that BF model you can flip a switch and it will let the drag out that will make an audible cycling sound when the fish runs with it. You can flip it up and go back to whatever drag setting you have and set the hook....at least that's my understanding.
The Diawa is the highest rated . Can't seem to find many who have anything bad to say about it. It does lack some of features of the Kast King but do I need em? I guess it's a quality vs versatility thing, although many say the Kast King is a strong underdog performer.