Hello! I am new to LimeSurvey and using LimeSurvey Cloud Version 5.2.4

Briefly, I am wanting to randomly assign participants to groups with equal sample sizes, if possible. I am then wanting to track participants in each group across multiple surveys. 

Here is an outline of the process I am trying to set up for context, with my two questions embedded:

1. Participants will be recruited using SONA Systems and redirected to an initial survey. 
--> The individual ID numbers generated by SONA will be recorded using the panel integration feature in LimeSurvey
--> To my understanding I will then be able to view this ID number as an answer to the short/long text question I build in.

2. All participants will complete the same initial survey, but I want to randomize them into two groups for future surveys.
--> I have created a hidden question to randomly assign a value between 1 and 2 (using the equation question type and {rand(1,2)} in the question box)
Question 1: Is there a way to encourage equivalent group sizes in this process? I understand that how I have it set up currently that would be out of my control. 

3. Participants will then be sent daily links to a series of short surveys to complete. These links will be sent via text (using an online texting platform) rather than email. Each survey must be completed on the day they were sent to the participant, and I need to track each participant across the series of daily surveys.
-->  I believe this will require me to embed the participant ID into each URL I send out for every participant.
Question 2: If this needs to be done manually (let me know if there's an obviously simpler method), could I simply use the "add participant" function in the following surveys, and insert the participant ID as the access code? Then retrieve the link for the given survey and participant from the participant table?
--> I assume If I create an attribute for "phonenumber" I would be able to use that to store the phone numbers alongside the participant ID numbers in the survey participant table, and that if I am progressively adding participants manually I can set the relevant access dates/times as I do this as well. 

4. All participants will complete the same final survey. 

Please feel free to correct me on any of my assumptions or suggest alternative methods! Again, I'm new to LimeSurvey so this is just what I've been able to figure out so far with the manual and forum. 

Thank you!