If you choose Matagalpa get there early on Tuesday and maybe that day you could hike up Cerro Apante. The next day could be for Selva Negra (cloud forest). If you choose Esteli you could go to the Somoto Canyon and maybe even stay overnight. Or El Tisey or Miraflor overnight.

As you arrive very late stay in Managua as you will take the bus from Managua (hopefully early) the next morning to Matagalpa or Esteli.

I would not go to Jiquilillo during Semana Santa. The beaches get crazy busy. It would be better to go there after Easter. It is 3 hours from Leon by bus. Chinandega was only interesting to us as a base to hike up volcano San Cristobal.

While you are in Leon for Easter will you have time for the volcanoes? I don't know if you like to hike but Cerro Negro and the overnight Telica camping trip are great. Maybe on arrival go to Granada and spend a day there and then go to Leon a day earlier and include the volcanoes. Or start with Granada and day trips (Masaya, Mombacho, Laguna de Apoyo...) and then go to Leon and go to the northern highlands after Easter when you have more time.

How long do you have? Ometepe is great. So is the Rio San Juan but you need time for that area. I like Los Guatuzos.

It is hard to give advice without knowing your interests (colonial cities, hiking, wildlife, volcanoes, beaches, surfing?). With 14 days I would go to Leon for the city, volcano Cerro Negro and volcano Telica (overnight camping trip). And Las Penitas for the beach. I would spend a day in Granada (city, isletas and evening visit of active volcano Masaya). A day for Laguna de Apoyo and Catarina. I would also go to Chocoyero-El Brujo (and I would stay overnight). Maybe a day for volcano Mombacho. Three days Ometepe with a volcano climb, Charco Verde nature reserve, Ojo de Agua natural spring pool, San Ramon waterfall... If you wanted to add Los Guatuzos (Rio San Juan) for wetlands, rainforest and lots of wildlife you would have to skip something else.

I think you can get from Ometepe to La Fortuna or Monteverde in 1 day's time if you start from Ometepe on the first ferry out. Don't ask me the directions; starting from Nicaragua I've only ever gone straight to San Jose. But I got to San Jose in 6-7 hours time starting in the morning from Ometepe. Monteverde might take a couple more hours because the roads there are not good.

In Cahuita there is a woman called Marion who rents an airbnb room right near Playa Negra for around $10 US per night. I stayed in January, and it's in the real jungle there. I just checked and it is available for some nights the week after Easter. Titled on the Airbnb website "Marion's room 2".

if you take the main roads they are paved between Tamarindo and Ostional/Nosora. But the roads leading into these two towns have portions that are gravel, though dry season won't be a issue. The coastal roads, connecting these areas, will be dusty and bumpy and possibly rutted, but fine.

As for buses from Ometepe to Rivas and the border, I have no idea, most likely yes. But its much faster to just taxi hire from San Jorge (ferry dock) to CR Border...

The buses from CR border to Liberia depart every 20-30 minutes, figure at least 2 hours to Liberia.

I have hiked up a lot of volcanoes in Guatemala and Nicaragua. You should really consider going back to Guatemala one day because some of my favorite volcano hikes are there (Acatenango overnight, Santa Maria, Tajumulco overnight). In Nicaragua: Cerro Negro is just a short hike up but I do enjoy the active crater, the views and the boarding/running down. I love Telica but I have always done the overnight camping trip. The crater is very impressive. It is often steaming a lot which makes it hard to look inside (if you are lucky you might see lava) but it is amazing nonetheless and you can stand right on the edge.

Masaya (near Granada) is great but has been very active so you are now only allowed 15 minutes or so at the crater. It is not a hike. They drive you right up to the crater. Again, it depends a bit on how much steam there is but with a bit of luck you can see a lava lake in the crater. I have only seen Masaya before it was this active and it is great to see the volcano during the day as well as you can see the scenery but if you want a better chance of seeing lava you should go when it is dark. Mombacho (also near Granada) is nice and has trails in the cloud forest but you will go to Monteverde which is cloud forest too so I would not choose Mombacho. On Ometepe there is Concepcion and Maderas. Both tough climbs. Maderas has cloud forest and there is only one viewpoint, not that high up. You really do the hike for the cloud forest and there is a crater lake at the top but it is almost always shrouded in clouds. Steep, muddy hike. I had to laugh at the G Adventures description: "at the summit, hike down into the crater and swim in the cool, refreshing lagoon. How many people can say they have floated in the bowels of a volcano?" Well, not me, because the water did not look inviting at all! Concepcion is really hard and the worst part is after the viewpoint and also going back down is very hard. I thought it was amazing to be at the crater rim although we couldn't see anything (it is often cloudy at the top) but we could feel the warm earth and it was very windy and grit was flying around... it was just a surreal experience. The good news is that the volcanoes are great to just look at as well. You will see them from the ferry and from almost everywhere on the island. As you only have one full day I would focus on seeing the island: Charco Verde nature reserve with nature trail (see monkeys and birds... best at dawn or dusk), small butterfly place, beach (go for a swim) and next door Chico Largo Adventure, fun ziplining with great views. Also don't miss Ojo de Agua, a natural spring pool. Or maybe kayaking on the Rio Istian. Or the San Ramon waterfall hike. Oh, I see you are doing a homestay on Ometepe. That will be a good experience.