Thanks for reading @presentminded!

If I am reading this right the Dfinity model will completely change the economics and incentives for mining ala Bitcoin and drastically reduce block compilation time lag by using less verification nodes using notaries instead of proof of work?

yep!

Also using different encryption and random assignation of nodes to protect block integrity with threshold verification levels to prohibit dropped blocks from unresponsive nodes?

It isn't really dropped blocks from unresponsive nodes, its more a different more efficient way to select nodes. There won't be any "dropped" blocks in Dfinity because every block that's on the chain will have been notarized and therefore finalized. Even if the node drops off the network, when they come back, they'll still know which chain is the best, similar to Bitcoin.

I can see many use cases for Dfinity but what are they aimed at primarily?

In one video Dominic claims they're trying to build a platform that a decentralized Uber could run on. The problem with doing this on Ethereum is the block finality time is too long.

Can it be layered in a stack protocol like Lightning is attempting to do on top of the Bitcoin blockchain?

No, Lightening is at the application layer. Dfinity is different from Bitcoin at the fundamental protocol layer. It will have smart contracts like Ethereum though, so developers will be able to build endless applications on top of the protocol.

Are all blockchains basically same satoshi program with different use cases or are they as different as MS, Apple, Unix architecture?

Hmm interesting question, maybe I'll write a post about this. I would say some blockchains are basically the same "Satoshi program", and some are as different as MS, Apple, and Unix. In the case of Dfinity vs Bitcoin I would say they're as different as differing OS.

How does one invest/moneytize blockchain app such as Dfinity without either buying their tokens before/after ICO which is speculation or write code and get paid in tokens (slightly lesser form of speculation).

It's my understanding with Dfinity that block producers will be paid in block rewards much the same way it is with Bitcoin mining.

I want to invest in Lightning but have no clue how.

Unless the developers inject crypto economics into the protocol usually you won't be able to invest in layer 2 solutions. I suppose what's adding to the confusion in crypto is often developers are adding tokens to things that don't need to be tokenized.