Look for a small screw-in plug on top of the thermostat housing of your fides - my '96 Accord had one. It's the "burp" screw if present. The idea is to loosen it (do NOT remove it!) once you have the fresh coolant in with the engine idling and at normal operating temp until only non-bubbly liquid burbles out, then snug it down. If there's no screw, then your car will self-burp as you drive it. DO make sure you have the heater temperature control knob or lever ALL the way to the hottest setting - that insures that the heater core will get flushed along with the rest of the cooling system. After you've refilled your cars with fresh coolant, periodically slide the lever or turn the knob to the highest heat setting a few seconds for several days to purge any remaining air that might've remained trapped despite your best initial efforts. The "big three" Japanese automakers all use essentially the same antifreeze philosophy regardless of marker dye color. If you want to stay with a Japanese OEM antifreeze, shop for the best price from a Honda, Nissan, or Toyota dealer - they're all close enough chemically to be interchangeable regardless of Japanese engine design and make. Conversely, if you want to save some $$$, buy a jug or two of Zerex G-05. While G-05 isn't identical with the Japanese flavors, it will do nicely. (The Japanese philosophy is to replace unstable high silicate levels with phosphates for quick corrosion protection. G-05 uses stabilized reduced levels of silicates to achieve essentially the same quick protection. Both G-05 and the Japnanese flavors additionally use "OAT" (organic acid technology) for main, long term corrosion protection. G-05, under other names in Europe, has been in use for over two decades, so it does have a track record. (The Mercedes-Benz equivalent is factory and service fill in Mercedes-Benz automobiles.)
About loosening the drain plug(s) on the block . . . I've done it and gotten drenched. (Guess where you'll be in relationship to where the liquid falls if you're lying on the ground or pavement.) Some plugs are cleverly positioned to be behind the exhaust manifold - sometimes requiring that the exhaust manifold be loosened or even removed first. If a wrench can be fit to the plug's head despite close proximity to an exhaust manifold or other obstruction, keep in mind that you'll still need to restart the plug's threads after you drain the block.
(I'm not saying all block plugs are this difficult - just reconnoiter and plan ahead before you commit yourself.)
If your rides are currently using standard antifreeze (vs. extended-life types), you really want to get as much of it out as possible before going to the expense of an extended-life type. While it's time consuming, multiple distilled water flushes until the effluent drains water-white clear is the best way to achieve that short of removing the block drain plug(s). Finally if either or both your cars have radiators with plastic top and bottom tanks, they're somewhat more vulnerable to cracking if you're clumsy trying to wrestle the bottom radiator hose off. These cars do have radiator drain plugs. They're not the brass valve-style petcocks once common on American cars, though. They're an actual plug (usually plastic with a finger tab and an o-ring sealing washer - which likes to pop free and roll to the most inconvenient location - dog poop, storm drains - you get the idea*). The plugs may face toward the engine or straight down. You may have to remove a plastic air-flow piece for access. They might be tight enough to require a small crescent wrench to loosen, but do not use mechanical leverage when re-installing - finger snug will be fine.
*If you do lose the o-ring, you shouldn't have much trouble locating the right size at a home improvement center's plumbing department.
