I'll be more on the practical side of things

Operationally:
- As software developers, I would guess they work together as a team, so create a channel for long collaborations between them that includes face to face interactions with yourself and the onshore team if it exists
- If you have a travel budget, of course rotating team members around or bringing them on shore would help with their motivation
- Find out each team member's aspirations and work on supporting their development
- Delegate them to lead the team's discussions and morning stand ups (virtual ones) and then discuss with them things like what they realized from today's meeting that you never realized as a team member
- Allow them to propose their approach, discuss it and try to apply it and if it fails, make them fail forward (fail early and quickly, then be agile to adapt it towards success and learn from their failure)

Relationship with your team:
- In your 1:1s with them, make sure to learn one common thing between you and that team member, that will keep a good discussion every time you meet
- Create face to face meetings for the whole team that are just for fun and talking about non work related stuff

Hope that helps!