Good ways to implement 5e variant initiative in Roll20?

Good afternoon, y'all. I'm currently exploring the possibility of using a variant combat order in my D&D 5th edition campaign. There are a couple of different ways to handle this — on the rules side — so one of the ways I want to evaluate the different options is based on how easily I can use Roll20's interface to simplify the recordkeeping. I'm happy to incorporate API scripting (preferably working from existing scripts, but if necessary, writing my own.) In broad strokes, here's what I'm looking for: New combat round begins Characters declare their action Initiative is rolled Characters take their actions The DMG variant uses a speed factor modifier on top of the initiative, such that, depending on the type of action declared, they get an additional bonus or penalty to their initiative. If we went this route, it would be great if players had an easy way to declare their action at the start of every round, which automatically adjusted their speed factor, and then, once declarations were in, the DM could fire an "update-initiative" script which would re-roll initiative for all tokens in combat and sort the initiative order accordingly. Alternatively, we could use a more B/X D&D style system where initiative is rolled by side, but actions are resolved in order based on the kind of action. (So side A moves, then side B moves, then side A fires missiles, then side B fires missiles, then side A fires spells, etc.) Less math to worry about here, so maybe this just needs a few quick action declaration macros that whisper to the GM. Anyway, I'd love to hear how others, if any, are handling these situations.

I'm not handling this right now, but If I did it, I'd use the new API Buttons in Dev. When the DM hit's the Begin Fight macro, it would whisper a menu of buttons to each player, for each character they have in the initiative (or via some other configuration), they would choose the action for that character, and the script adjusts their roll as needed.

Method 1: Create the macro to refer to a bar on their token. They can then set the token bar to 0, 1,2, etc depending on the action type they're going to take. Method 2: Create a separate macro button for each action type, grouped by action speed. Method 3: Single macro containing a roll query to ask the player what their Speed is as they roll it. *** There's an inherent mechanical pitfall to this method, however: How will you handle player actions that are no longer valid? Ie: If Player 1 declares "I'm going to shoot an arrow at Monster A" and Monster A moved out of range before Player 1 goes, what happens to Player 1's action? Do they just lose it and do nothing? Do they get to choose something else? etc. If using All Players go then All Monsters go, you may still run into the issue of Player2 killing off Player1's target before they go, or other similar toe-stepping.

Using the API buttons to present players with the appropriate macro buttons when combat begins sure sounds like the sweet spot. One more cool thing to wait for. As for invalid actions, Mark, yes, if you choose not to take your declared action, or it becomes invalid, you cannot take a different action. It's a little bit like readying an action. Fortunately, the declarations are allowed to be pretty vague — melee with my longsword, ranged with my crossbow, fire a level 2 spell, etc. So you don't have to declare the specific target for your actions until your turn in the initiative order. But, the idea is to make combat a little more chaotic. Which could be all frustrating and not at all fun, but I'd like to give it a try. The B/X model ends up being a little stricter, because you have perform all movement before any other actions are resolved, so things get a little trickier if your combat is really spread out. Not a bad thing, but we probably won't go that route because the sword of cinematic run-and-slash style of 5e is definitely something my players take advantage of. (5e allows you to break up movement, so a 5th level fighter can run 5 feet, cut down a goblin, run another 10 feet, cut down another goblin, take an action surge and run 10 feet further to make two attacks on an ogre. That wouldn't be possible in B/X style combat order.)