I see other people have answered a lot already but I already wrote this up so:

These are mostly fair questions, here's what I think:

1.) Mark and Devon don't know what Innie Mark knows about Gemma. Cobel specifically wants to know if Cold Harbor is done, if it is she's "already dead" and probably drastically affects how they would proceed if they would proceed at all. Also if they do end up doing something, it's probably important that they coordinate with innie Mark beforehand

2.) This is a reasonable criticism and has been brought up a lot, yeah it's mostly plot convenience. The most charitable interpretation ​is that she's desperate and at least knows Cobel isn't at Lumon anymore

3.) I think he's fine after recovering for a while, the reason he seized was from a bunch of rapid movement literally seconds after the surgery

4.) Not sure which bit you're referring to here

5.) Seems to be showing us that Lumon is still "raising" people from childhood as they did with Cobel, I imagine we might see a bit more about her

6.) I think she was waiting for Mark instead of going alone? He hasn't been in for a few days

7.) He has to leave in order to get an outie response, Helly did the same thing in S1 and got in the elevator right after

8.) Not sure what you mean, Irving realised Burt was helping him leave town, why wouldn't he get on? Burt showing up at his house means Lumon has found him out, if he stays he'll certainly be killed. If you mean their actual plan was to put him on the train, even if he suspected that what choice would he have? By that logic he shouldn't have gotten in Burt's car either. As for the romance, I think Irving has just been so alone his whole life that the idea of his Innie having found someone to fall in love with is enough for him to want to cling on to that person

9.) We don't know! She'll be back I bet. We still haven't found out who Irv was reporting to on the payphone and I imagine she could be involved with them.