Oof.
I think I know exactly what's going up. Look around for "Honda Odyssey VCM Misfire". I would just probably forget about the coils for now.
Basically, your van, my van (a 2014 EXL), and most other Hondas with SOHC V6 engines manufactured in the last 15 years has an active cylinder deactivation function called 'VCM'. Whenever you see the 'Eco' light on your dashboard, between 2 and 4 cylinders have been 'deactivated' (no fuel or spark to that cylinder) to improve fuel economy. Sounds nice, right? Well, it's not so nice - Honda (well actually, most manufacturers) did not implement it very well and for a number of reasons that forums/Google can go deeper into, the two cylinders most frequently deactivated can become fouled with oil & carbon buildup and/or a host of other problems.
The most common issues that occur are 1) misfires because the spark plugs are fouled and 2) bad vibrations when gears change or the engine starts because the active engine mounts have been damaged by the various cylinders coming on and off.
I would take your van to a reputable Honda mechanic (not dealer) and explain the issue. I can't tell you what the fix will be, because it all depends on how bad the VCM treated your engine. Many owners go a whole lifetime of the van and never have issues. Others have tons.
You SHOULD seek a fix, though. If you can get past this, are changing the transmission fluid every 15k miles, and know that the timing belt service was done at 105k miles, your van will absolutely last to 200k.
If you're interested in preventing the VCM in the future, research Honda VCM Muzzlers.
Good Luck!