Looking at the list, if you want to use the mediocre pike available through the Phyrrus in Italy option you have a mandatory Samnite Msword. That seems a good place to start. If converting the list to fit myself, the 1st question I ask is whether I want to win terrain or merely to contest it. The second, and closely related, is if I concentrate my MI or disperse it. Third question, also interrelated with 1 & 2, how much do I want to risk the MI being a target if there is no terrain to get into.
Lets assume I want to to be able to make bids to contest or win both flanks of my line (combining corps I & II). Lets also assume I want to emphasize winning the terrain and am not very worried about being caught in the open. You say the list is at 199, so I have 1 point to work with. The easiest approach is to drop 2x pike (1 ordinary and one mediocre, returning 11 & 9 pts, if memory serves). 12 pike is an enormous number and leaving it at 10 is still more than enough to be extremely impressive. With 21 pts we could take 3 MI swordsmen and call it a day. These would be a pretty good contesting force for terrain when concentrated. If the list has javelinmen (not having my book in front of me, I do not know, but Peltasts are very common in greek/hellenistic lists) then one of them might be nice, but reduces the chance of winning a terrain piece rather than just contesting it. Maybe deploy the two sword with one command and the jav with the other. Now you can contest both flanks, if not for very long or very effectively against determined attack. This is literally intended to be a holding force for the main line to get past and into the clash long enough to get a few rounds of dice before a decent enemy terrain command can move on the their flanks. These troops are expendable if their deaths contribute to the pike going unmolested for longer. They also do not want to charge in before they absolutely have to. I.e., they do not want to start their fight while they are a move or two ahead of the HI. That risks seeing them killed before the pike can pass and now you are back at step one.
Looking at further options, the brilliant general with just 4 horse, two of which are unable to evade, is probably an extravagance. With him your initiative bid is only a +1, so you can assume that you will lose initiative anyway. If we demote him to competent we free up 3 points. These can add impact to all three MI. However, getting a 4th MI would be great, since I said I wanted to contest both flanks and that lone sword/jav looks pretty lonely and outmatched. Right now our army count is +1 by trading 2 pike for 3 MI. I also am dubious of of all those mediocre Hspear. They are probably the bookends of your line, owing to their agility and speed (relative to pike, of course). They are the troops you want to be able to turn to wall off a flank threat if your MI fail (or the terrain forces the MI to hide elsewhere - say an open side of the board with some strong charging cavalry units out there). I think we want these to be ordinary. If we drop two, we can upgrade the other two to ordinary and leave 8 points. That is enough for another MI + 1 point. If we accept the general downgrade we have 4 MI sword + 4 points - enough for 4 upgrade to impact, or two upgrades to elite. Season to taste. You then have two decent terrain presences to shield the ends of your line. If the enemy only has one terrain command, one of yours will go down for sure. But you will have the opportunity to walk through the other and try to pry open their flank. If your line gets separated from the MI you now have a much more stalwart Hspear to turn and try and block off the easiest paths to flanks. Your battle line does shorten by 4 HI, but it is still 12 wide and its average quality has gone up a little. Plus there are plenty of circumstances where the MI are practically as good as the heavies at extending the line.
If you want to focus on having MI that are safer to stand out in the open and extend your line, then you will want to work in the Hypaspists (Mspear elite) for 9 pts each. The easiest path I see is dropping impact from all 4 MI and using those points to convert 2 swords over to them.