NOOB pre-license question.  Could two radios communicate on the same freq a nearby repeater is using with offset and/or a tone programmed without interfering?

Thanks

if you are using the same offset and same tone then you are going to be keying the repeater. if you use simplex(no tone and no offset) then yes you can communicate without messing with the repeater.

Regardless of the differing tone or no tone, you will interfere with the transmitter as soon as someone with the correct tone brings the repeater up.

With all of the other frequencies available just pick another frequency.  Why interfere with a repeater that everyone in
the area may depend on?

Could they? Yes, kind of. They would have to be set opposite. The repeater frequency is the listening frequency for your radio. However, the offest would make the listening frequency for the other guy the input frequency for the repeater. And, if you use the same tone, the repeater is going to key up.

What are you trying to accomplish?

No.  Even with tone off,  you will interfere with repeater operations if they are concurrent with your transmissions.

Depends on whether you're talking about the input or output frequency. There is a mode on most commercial radios called talkaround, where you are actually transmitting on the repeater output frequency. But if anyone keys up the repeater while you're transmitting on the same output freq, there will be interference and it'll probably sound like a warble to whoever's listening. But it allows you to use the radios when the repeater is down.

Or when running semi local but still want to hear notifications/status updates on the repeater. We do it a lot for races when we want to notify someone local to meet on the simplex frequency as well as I know a bunch of farmers using this technique to not put undue traffic on repeaters.

This really depends on how the repeater and users configure their radios. 90% of hams don't run RX PL on their radios and about 40% of repeaters just transmit CSQ on the output. So if Hams are listening via CSQ, they'll hear transmissions in range regardless.

I'd go with these answers: No

If you transmit on the repeater's input frequency without a tone, your signal will be gated by legit users using a tone and you will come through the repeater. You will interfere with the input signal if you are strong enough to reach the repeater, tone or not.

If you transmit on the repeater's output frequency, anyone listening to the repeater that is within your range will hear you. You may interfere with legit signals from the repeater's output even if you are not delivering a full strength signal. The capture ratio matters and your signal strength vs the repeater will determine how badly you disrupt the repeater signal to the listener.
Precisely.

With so many available simplex frequencies I'm not sure why anyone would do this unless you are just asking for curiosity reasons.

You will cause interference if anyone is trying to use the repeater at the same time.

They would also cause interference to you.

It makes no sense and would be bad amateur practice if not intentional interference.

Use designated/bandplan simplex frequencies for simplex operation.

One exception is the previously mentioned scenario of a repeater being off the air, particularly in an emergency situation, where folks will often operate simplex on the repeater's normal output frequency. In the LMR world that's called "talkaround".

 
This.  The PL tone simply prompts the repeater to key-up.  If a Tx sans-tone happens simultaneously as a with-tone Tx the sans-tone Tx will interfere while the with-tone Tx is transmitting.  In other words, the repeater will pick up anything on its input frequency as long as at least one signal is received with the proper tone.