You’re welcome!
About the Ints and Floats from Arduino, they have to be broken down into 4 byte groups before being sent, respecting endianness. Then, using ReadInt etc in Unreal will re-group and interpret the next 4 bytes in the serial port. For examples of breaking ints and floats in Arduino and sending them to Unreal, take a look at the ArduinoTypesExample.ino file in the plugin folders. The float method in the example works for both floats and ints. The int method works only for ints.
For working with more than one variable, you can have synchronization problems. For instance, Unreal could start reading when Arduino has already sent 2 bytes of an int, making Unreal receive only the last 2 of them if you used flush on BeginPlay. And you should, because if you don’t, you might get all previous data in the port (and it could be a lot).
To solve the synchronization problem I use a “protocol”. I described this method in this post.