Its a given certainty that Lando will appear and its pretty much unthinkable that he wouldn't. Why?
Firstly, his friendship with Han means he MUST turn up for the funeral/memorial. And its quite likely its there he will meet Chewie , Leia and probably Finn (and he'll also possiby get reaquainted with the Falcon again given his history with the ship !!!!!).
And I'm guessing this is where another plot line will begin. Given he is Hans friend its quite probable that Han may have left a final request with him in the event of his death or that Leia recruits him back to help the resistance for a mission.
Whilst Lando may not be able to complete it by himself alone ,given his age, Chewie ,Finn and Poe in the Falcon would. Which would also nicely leave Rey with Luke long enough to explore their backstories for her training to continue uninterrupted (apart from that fight with Kylo and the knights of Ren!!!).
Given that both Han and Lando were both well known all round rogues, gamblers and smugglers I would bet there is a really strong connection to that "Casino" Planet.
Although the world has not been named yet its a fair chance that it might be Corellia , as that was Hans planet of origin. Interestingly its the origin of many well known space vessels that were crafted in the large orbital shipyards above the planet (including the Falcon and the Blockade Runner!!!) . Which would also kind of nicely tie in with the fact that many of the dock workers may need the rich gambling and drinking joints which we've seen pictured in Croatia and that the criminal gangs are there present on world to exploit it. Wasn't there a rumour that Benici Del Toro was a crime boss???? Might we also see Hutt again???
And that may also explain why we didn't see the much of the Imperial dockyards as promised for Rogue One. Its also the kind of shadey world and set up that Rian likes ,given his appreciation of Cowboy Beebop and Brick and Looper which he wrote. I would certainly love to see the place where the orbital shipyards are. Plus there are other planets close by within the Corellian system and its had such a rich history thats just not been very well explored within the films up until now.
It also brings up various possibilities that Han may have had an early "family" left there.Perhaps its that which Lando tasks Finn and co with finding , I could see Han wanting to leave something to an estranged daughter or wife. OR perhaps its that Lando needs help to fight the crime syndicate if its supported by First Order networks, so that he can get the rebuilding contracts for the Resistance fleet back underway.
Its also possible that if they re establish part of this Corellian backstory here in VIII they can then go back and explore it (somewhat like Rogue One) in the Han Solo standalone (and then reuse some of the sets!!!!).