- Bitcoin (keeping SegWit functionality and keeping the limit on block size at 1 megabyte)
Might as well make this correct when someone did ask: Keeping the segwit functionality where fixed max block size is removed. The allowed size is now dependent on the types of transactions used resulting in blocks of up to 4 megabytes.
- Bitcoin (keeping SegWit functionality and increasing the limit on block sizes to 2 megabytes)
Same here but up to 8 megabytes.
Making a backwards compatible block size increase was one of the design factors behind segwit. I'm sure you've heard about it by now, the documentation has been updated and is actually rather good so you can get all the technical details there.
the one with the 1 megabyte block size limit "SegWit"
This is really misleading. Search the source code for "MAX_BLOCK_SIZE", or "1000000". You won't find it. Because there is no such limit.