Migration of a public private key pair

All -

A few questions… Let’s say I own a private key pair (from before the DAO fork) that still has some ETH (orig) on it (in paper form)…

Many of us gave ETH as gifts to friends and family (a long time ago) as gifts etc.

My question is related to the migration to ETH2.

Specifically, with the beacon chain starting in 2020, there are two fundamental groups / scenarios that I can see. Voluntary migration and involuntary.

Folks that make the initial voluntary migration, lets agree are clearly sophisticated and know what they are doing (in theory). As time goes on during the voluntary migration, the user base will shift from more sophisticated to just the average user wanting to engage on the ETH2 network.

The questions I have surrounds the involuntary migration. The folks that totally forgot they had a paper wallet from years ago (including genesis to before or after the fork).

So, here are some of the questions. Will the state and the balances be “copied” over to a shard?

When will that occur?

How will economic incentives stay high enough for sufficient PoW mining to fend off a 51% attack before that migration? (Eg… the last miner standing problem)

Specific to that last point, in my eyes, the only way it makes sense would for their to be some date… and then have it be randomly selected after date X … but between Y & Z… such that mining incentives are still more or less enough to defend a 51% attack.

Will the ETH1 network continue thereafter? If so, wont all of the “copied” involuntary migrated addresses now have a double spend “issue”?

Very much appreciate any insight on the above. Just your average ETH guy wanting to know I need to get my mom to do a migration or just sit tight!