Chris, a lot of those add on items are not entirely necessary with a basic LiFePo4 installation, though I would want to add a class T fuse to the list of mandatory items, something many people do leave out, at a cost of around $50.
Beyond that many existing converter/chargers will function acceptably, if not optimally with LiFePo4 batteries, though this evaluation needs to be done on a installation to installation basis. In my own LiFePo4 installation I am using the same Progressive Dynamics PD9260 converter that the previous owner of my coach installed in 2015, it works ok for the job, though it may be a little slow fully charging, and may potentially drop out of 14.4V bulk charging mode before the batteries are fully charged due to its built in 4 hour time limit on bulk charging mode, unless the manual override button is pressed. (4x60 amps = 240AH max charging before dropping out of bulk charge mode, I have 420AH worth of LiFePo4 batteries). It would then drop to 13.6V float charging which would eventually bring the LiFePo4 batteries up above 90% charge. (the 400 watts of solar panels would then fully top it off if parked outside under sunlight in short order)
DC-DC chargers primarily are used to protect alternators from being overloaded and are generally not needed on smaller LiFePo4 installations under about 200AH in size, which would account for probably the majority of basic installations. DC-DC chargers are also getting cheaper all the time, and a 20A model is now available on Amazon for under $100, such units should be simple to install inline with the existing charging cable adding no more than 20 or so minutes worth of labor in most installations.
So yes there may be some added expenses converting to LiFePo4 batteries, in a basic installation they don't need to cost all that much, perhaps an additional $150-$200 in most cases, maybe less. Add to this that many newer converters are coming from the factory with official "lithium" support by way of a jumper setting, etc. and the this may be get even cheaper in the near future.
2002 Safari Trek 2830 on P32 Chassis with 8.1L w/ 400 watts solar 420Ah LiFePo4
2017 Jeep Cherokee Overland & 2007 Toyota Yaris TOADs with Even Brake,
Demco Commander tow bar and Blue Ox / Roadmaster base plates