Depending on the brand and model of the recessed fixture housing you are replacing it is possible to replace the components of the fixture. As an example, a Halo 274IC uses the identical plaster frame, J box and hangar bars as the H7ICT. The ballast is attached to the removable cover on the J box. All of these parts are required to be field replaceable through the plaster frame hole without damaging the ceiling. It's not fun but it can be done. It's also possible to upgrade to a higher wattage fluorescent by the same method if available in the same fixture size. Here is a link that might be useful: Halo example

If you're talking about a fixture with individual diodes in place of the traditional screw-in bulb, then you'll almost certainly have to replace the fixture. With can lights you can use a type with replaceable LED/trim unit. I've been converting my lighting to LED over the last 4 years. The only failure has been with screw-in type bulb. If it's a deal breaker, just select a type that uses a replaceable bulb. LED is vastly superior to compact fluorescent IMO.

There's lumens for a work space and ambient lumens. Both can be on dimmers. When you're working on something at a counter, cooktop or sink 450 lumens at the counter is recommended. And you should place the light source in front of where you stand to avoid creating a shadow on your work. Under cabinet leds can help light a work surface. For ambient recessed an inexpensive standard can that accepts an A19 traditional bulb can take a 100w equivalent 11w led you can get at Costco. That provides a lot of light for a broad area. Can and bulb for about $20. A 2" recessed 1500 lumen remodel can go for $100-150 from Acuity Here These should be 3-6 inches in front of the edge of the counter or centered above a sink or cooktop if possible

I do not believe that six cans and a lighted ceiling fan is overkill for your living room, so I would add back in the ones you removed. I have 11 cans plus a center chandelier, and lighted built-ins (and lamps of course) in my family room. My room is 20x20. The more lighting you have, the more control you have on mood and atmosphere as long you have dimmers on specific groupings of lights. Most homes I’m in are completely under lighted and also have dark blank areas with no lighting at all. My husbands study which is 16x16 has 6 cans and a central chandelier and the room has ample lighting (not overkill at all). All my lights are on dimmers. I would also add two cans directly above the head of your master bed. Comes in handy when you need to read or look closely at anything while in bed. Of course I would still have lamps or sconces by/on night tables, but they will not give you the kind of light you might need for reading or close viewing etc while in bed. Also advise having additional switches by your bed to control all your lights. When you’re all comfy it’s nice not to have to get up to turn off your ceiling lights. And even though your secondary bedrooms are not that large, my suggestion would be to add 4 cans (in addition to the central ceiling fixture) because I would want more even lighting than 2 cans can provide (would make sure everything is on a dimmer) One thing I would consider is smart lighting which actually helps to cut down on the necessity for hardwired 3 and 4 way switches. When we built our home I had the electricians put 3 and 4 ways EVERYWHERE which was an added expense and the wall switch plates got very crowded with so many switches. After living there for a while we started to add in Lutron Caseta smart dimmers and found that it would have been much less expensive (and much simpler) to have single pole switches installed by our electrician and just replace that standard wall switch with the Caseta dimmers. With these single pole dimmers you can purchase tiny remotes and put them anywhere (you can have a 10 way switch if you choose by placing multiple remotes wherever you want). Lutron does have smart dimmers for 3 way switches, but they are more expensive and replacing the original switches gets a little more convoluted. So....wherever you think you need a three way switch, consider doing a simple single pole and use the Lutron Caseta’s with their remotes. You can even have your electrician install the Caseta’s initially instead of the switches he may be planning on providing. There is also an app which enables you to control all the lights remotely on your phone, set up schedules, etc. That will require their hub which is around $100, but the dimmers and remotes do not need the hub to operate.