I would not consider heating and AC part of plumbing.

Rough plumbing... Do you have a plan? Is the plan part of the contract? Are there bath drains (esp in the basement) in the plan?

is... AC considered to be part of plumbing?

Only in the unlikely case that you are using watercooled air-conditioning in a single-family residential setting.

I dont have a formal plan for finishing the attic or basement. My intention was to make sure that I had the "guts" installed but not connected while all the walls were open to avoid the cost down the road.

you can have hvac company install ducts to unfinished
area that are dampered off at the plenum.
then when area is finished, you open the dampers.

having enough capacity of hvac will have to be
taken into account when system is sized.
including this area when load calc is done
is the best way to achieve this.

in the meantime, the hvac system will be
oversized for the rest of the house.
not a good thing if area is to be left unfinished
for along time.

another option would be to have system zoned.
and set tstat in basement for minimal heating &
cooling until area is finished.

you should talk to your hvac company about
your plans & time frame to finsish basement.
get their recommendations.

best of luck.

Are you putting drywall up in these areas?

There are rules about how long a supply line (for water) can be and not be connected to anything (ie, capped off). I think it is only 12 inches.

If you don't have a basement plan and plan to put plumbing in it, your drain lines are going to have to be put in using a jack hammer at some later time.

For the attic, without a plan, the best you can do it plan to put your future bathroom near the current vent stack/drains, or make sure there is a 2x6 in wall on the first floor near where you plan to put your attic bath so the plumbers can come in at a later time and put a drain line.

You'll also want to make sure your system (main line to sewer or septic) is sized for whatever your future needs are.

I am just (currently) going through a remodel where we converted attic space and added a bath. Turns out, that wasn't that difficult in my house. But, the question we got lucky on, and wasn't in my radar at all was "how many toilets will you end up with". If 3 or fewer, in my area, you can have only a 3" main line to sewer. If more than 3, you need 4". I'm not sure what is standard building these days (maybe it is 4") but you'll want to make sure the capacity of whatever you put in will be great enough for what you plan.

Electric is relatively easy to put in/remodel around. Have them put some conduit into the walls from the main area to the attic and basement so it is easier later to run the wires to the places they'll need to go.

Realistically, though, your basement plumbing plan is best figured out now, imo.

I dont have a formal plan for finishing the attic or basement. My intention was to make sure that I had the "guts" installed but not connected while all the walls were open to avoid the cost down the road.

It will do you zero good to rough in plumbing without a plan for the space fully in place. There are very specific requirements for how baths need to be laid out, so you need to design them now, even if you don't construct them. Just putting a drain "somewhere" won't work. It has to be in the right location, or you might as well pay for all new plumbing to be done down the road.

And as ERLA says, oversizing your HVAC now leads to many more problems than just planning for a complete separate HVAC unit for the expansion space whenever that happens.